Yesterday I made a backup from Kodi (RPi4 LE 9.2.5) which produced 300 mb file at /storage/backup/. When I tried to copy it to my computer using WinSCP, it starts, after few minutes drops speed, says it will take about 60 minutes. If I am watching something on that RPi at that time, it will hang (regardless of the source). I can not even ssh to it! It takes some time for the problems to appear, maybe 10 minutes (yes for a 300 mb file). At the end, WinSCP says it had enough and bails out permanently. I was not able to copy file from RPi.
When LE is hung due to this issue and I end the file copy, LE regains normal function immediately.
a) I have tried 2 different RPi4, both connected to Giga LAN, both choke on 300 mb file scp.
b) they have different cards, one is 8 GB another 64 GB, both Sundisk (original).
c) copying the same file from an RPi 2a LE7 using the same 8 GB card as in a) and b) works flawless in about a minute.
Finally, I mounted this folder to my file server and made a backup directly to my server. This 300 mb file I then used to test by first copying it (WinSCP) to RPis and then trying to copy it back. This is not caused by the MicroSD card.
When I (WinSCP) copy a 75 mb backup from the second RPi4 it is copied normally. Earlier, I used mv to move some 20+ files in GB sizes from MicroSD to a mounted file server normally.
Seems like it is a problem with LE 9.2.5 and SCP for files of certain size e.g. 300 mb.