Check out: Memory leak since 1.19.1.2701 (possible > 1.19)
There’s no solution there but you’re not the only with with issues. I’m not sure if it’s a memory leak (it doesn’t grow gradually over time) but just poor memory allocation.
Starting a new thread (as you’ve done) is also a good idea as the Plex staff/moderators seem to read the newer threads with greater interest than posts to older threads.