Error when reading from remote video files

attempting to analyze a collection from ETHZ we get errors of the following kind:

2020-07-21T09:39:56.937 indexer::DoPanic [server.go:137] > ERROR - cannot create validateav of /tmp/indexer065602559: error executing (/usr/bin/ffmpeg [-v warning -i /tmp/indexer065602559 -f null -]):  - : signal: killed
192.168.10.28 - - [21/Jul/2020:09:39:46 +0000] "GET /validateav/tmp/indexer065602559 HTTP/1.1" 500 218
192.168.10.28 - - [21/Jul/2020:09:39:56 +0000] "GET /exif/%2Ftmp%2Findexer065602559 HTTP/1.1" 301 0
2020-07-21T09:39:56.939 indexer::Exec [exif.go:72] > INFO - executing /usr/bin/exiftool [-json /tmp/indexer065602559]
192.168.10.28 - - [21/Jul/2020:09:39:56 +0000] "GET /exif/tmp/indexer065602559 HTTP/1.1" 200 1739
192.168.10.28 - - [21/Jul/2020:09:40:17 +0000] "GET /histogram/%2Ftmp%2Findexer073424722 HTTP/1.1" 301 0
192.168.10.28 - - [21/Jul/2020:09:40:17 +0000] "GET /histogram/tmp/indexer073424722 HTTP/1.1" 200 5
192.168.10.28 - - [21/Jul/2020:09:40:19 +0000] "GET /validateimage/%2Ftmp%2Findexer073424722 HTTP/1.1" 301 0
2020-07-21T09:40:19.704 indexer::Exec [image.go:57] > INFO - executing /usr/bin/identify [-verbose /tmp/indexer073424722]
2020-07-21T09:40:19.735 indexer::DoPanic [server.go:137] > ERROR - cannot create validateimage of /tmp/indexer073424722: error executing (/usr/bin/identify [-verbose /tmp/indexer073424722]):  - identify: no decode delegate for this image format `' @ error/constitute.c/ReadImage/560.: exit status 1
192.168.10.28 - - [21/Jul/2020:09:40:19 +0000] "GET /validateimage/tmp/indexer073424722 HTTP/1.1" 500 296
192.168.10.28 - - [21/Jul/2020:09:40:19 +0000] "GET /validateav/%2Ftmp%2Findexer073424722 HTTP/1.1" 301 0
2020-07-21T09:40:19.737 indexer::Exec [av.go:57] > INFO - executing /usr/bin/ffmpeg [-v warning -i /tmp/indexer073424722 -f null -]
2020-07-21T09:40:29.751 indexer::DoPanic [server.go:137] > ERROR - cannot create validateav of /tmp/indexer073424722: error executing (/usr/bin/ffmpeg [-v warning -i /tmp/indexer073424722 -f null -]):  - [mov,mp4,m4a,3gp,3g2,mj2 @ 0x558b53f888c0] st: 0 edit list: 1 Missing key frame while searching for timestamp: 0
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x558b53f888c0] st: 0 edit list 1 Cannot find an index entry before timestamp: 0.: signal: killed
192.168.10.28 - - [21/Jul/2020:09:40:19 +0000] "GET /validateav/tmp/indexer073424722 HTTP/1.1" 500 440
192.168.10.28 - - [21/Jul/2020:09:40:29 +0000] "GET /exif/%2Ftmp%2Findexer073424722 HTTP/1.1" 301 0
2020-07-21T09:40:29.767 indexer::Exec [exif.go:72] > INFO - executing /usr/bin/exiftool [-json /tmp/indexer073424722]
192.168.10.28 - - [21/Jul/2020:09:40:29 +0000] "GET /exif/tmp/indexer073424722 HTTP/1.1" 200 5509
192.168.10.28 - - [21/Jul/2020:09:40:59 +0000] "GET /histogram/%2Ftmp%2Findexer661691853 HTTP/1.1" 301 0
192.168.10.28 - - [21/Jul/2020:09:40:59 +0000] "GET /histogram/tmp/indexer661691853 HTTP/1.1" 200 5
192.168.10.28 - - [21/Jul/2020:09:41:00 +0000] "GET /validateimage/%2Ftmp%2Findexer661691853 HTTP/1.1" 301 0
2020-07-21T09:41:00.245 indexer::Exec [image.go:57] > INFO - executing /usr/bin/identify [-verbose /tmp/indexer661691853]
2020-07-21T09:41:00.267 indexer::DoPanic [server.go:137] > ERROR - cannot create validateimage of /tmp/indexer661691853: error executing (/usr/bin/identify [-verbose /tmp/indexer661691853]):  - identify: no decode delegate for this image format `' @ error/constitute.c/ReadImage/560.: exit status 1
192.168.10.28 - - [21/Jul/2020:09:41:00 +0000] "GET /validateimage/tmp/indexer661691853 HTTP/1.1" 500 296
192.168.10.28 - - [21/Jul/2020:09:41:00 +0000] "GET /validateav/%2Ftmp%2Findexer661691853 HTTP/1.1" 301 0
2020-07-21T09:41:00.269 indexer::Exec [av.go:57] > INFO - executing /usr/bin/ffmpeg [-v warning -i /tmp/indexer661691853 -f null -]
2020-07-21T09:41:10.274 indexer::DoPanic [server.go:137] > ERROR - cannot create validateav of /tmp/indexer661691853: error executing (/usr/bin/ffmpeg [-v warning -i /tmp/indexer661691853 -f null -]):  - : signal: killed
192.168.10.28 - - [21/Jul/2020:09:41:00 +0000] "GET /validateav/tmp/indexer661691853 HTTP/1.1" 500 218
192.168.10.28 - - [21/Jul/2020:09:41:10 +0000] "GET /exif/%2Ftmp%2Findexer661691853 HTTP/1.1" 301 0
2020-07-21T09:41:10.276 indexer::Exec [exif.go:72] > INFO - executing /usr/bin/exiftool [-json /tmp/indexer661691853]
192.168.10.28 - - [21/Jul/2020:09:41:10 +0000] "GET /exif/tmp/indexer661691853 HTTP/1.1" 200 1739

The files are often quite large (~1GB), so that could be a potential problem. However, the log of the Indexer shows no anomalies:

2020-07-21T11:47:14.602 indexer::getContent [server.go:127] > INFO - loading from http://digitalisate.afz.ethz.ch/?&guid=c94cc7b82aeb4d7c94be67c4a753f4b3
2020-07-21T11:47:20.023 indexer::getContent [server.go:165] > DEBUG - mimetype from server: video/mp4
2020-07-21T11:47:20.023 indexer::getContent [server.go:169] > INFO - full download of http://digitalisate.afz.ethz.ch/?&guid=c94cc7b82aeb4d7c94be67c4a753f4b3
192.168.9.210 - - [21/Jul/2020:11:47:14 +0000] "POST / HTTP/1.1" 200 262
2020-07-21T11:47:30.032 indexer::getContent [server.go:127] > INFO - loading from http://digitalisate.afz.ethz.ch/?&guid=14051e2784f94fb7ae7380297e22e613
2020-07-21T11:47:37.565 indexer::getContent [server.go:165] > DEBUG - mimetype from server: video/mp4
2020-07-21T11:47:37.565 indexer::getContent [server.go:169] > INFO - full download of http://digitalisate.afz.ethz.ch/?&guid=14051e2784f94fb7ae7380297e22e613
192.168.9.210 - - [21/Jul/2020:11:47:30 +0000] "POST / HTTP/1.1" 200 262
2020-07-21T11:47:47.575 indexer::getContent [server.go:127] > INFO - loading from http://digitalisate.afz.ethz.ch/?&guid=669364e0a48244cabfe0a8380cec8b0a
2020-07-21T11:47:54.017 indexer::getContent [server.go:165] > DEBUG - mimetype from server: video/mp4
2020-07-21T11:47:54.017 indexer::getContent [server.go:169] > INFO - full download of http://digitalisate.afz.ethz.ch/?&guid=669364e0a48244cabfe0a8380cec8b0a