I have experienced several times a strange issue on current LE 11 Nightlies, installed on RPi 4B / 2GB at external HDD, connected through USB/SATA adapter. TVheadend server 4.3 + TVheadend client used.
It's a more or less random freeze of LE (did not even respond to PING, SSH console was frozen as well, no response to remote control and during that time there was an intensive HDD activity) and it looks it's related to TimeShift function which activated oom-killer.
After some time (up to several minutes) the LE usually starts responding again, even the SSH console starts where it stopped responding (without disconnection).
There are also some random issues with audio - sometimes audio does not start when I switch the channel - it's necessary to switch to another channel and back. Sometimes (usually when the live stream has a temporary corruption due to bad signal) it leads to freeze playing (a percentage circle appears on display and stops somewhere between 0-100%). Using TimeShift to move back or forward is usually possible (even though the TimeShift pointer gets confused and does not work correctly until stopped / started or switch to another channel). When I got back, the stream was playng until the problematic point where it freezed again. Unfortunately I don't have a stream recorded as it's not possible to save the TimeShift data (configured to use RAM only).
This is a part of kernel log, showing the several attempts to shift back before the freeze point: