Ram usage increases slowly after AFK at Spawners. (FPS decreases).

Dear,

 

I play on a Minecraft server and I afk spawners there sometimes. Whenever I play around the area with the spawners I have no issues.

 

The issues start when I am afking the spawners for X minutes. Slowly my ram ussage increases from about 5% to 99% and then after a while the came crashes with "exit code 1" (only gives this code in logs).

I first only had 2 GB ram set.

After that 4GB.

After that 8GB.

It all starts the same around a low percentage and then slowly walks it's way up to 99% ram ussage and then crashes. Doesn't matter howmuch ram I allocate.

 
My fps also slowly decreases when my RAM ussage increases. From about 150-200fps to just 5 fps after being afk there for a while.

My FPS gets better when tp'ing away.
Only happens when I afk there. When I play/fly around the spawners I have great fps/ram ussage.

I have added screenshots showing this behaviour.

I've tried keeping Minecraft run fullscreen and minimized. No other processes start on my computer while I afk there.

Java: 1.8.0_51 64bit
Minecraft 1.13.2 (1.13.2/vanilla)