Realms crashes and rolls back a few seconds

Realmowner IGN: Plagiatus

While developing a minigame on my realm I ran into the following issue:

The realm seems to apparently completely randomly crash *while the minigame is running* (it hasn't crashed while the minigame wasn't running yet).
I obviously use commandblocks, but I only ever activate those that I need when I need them and do everything in my power to make it as less ressource intensive as possible.

It completely undoes everything in the last few seconds before the crash (see attached videos), including not counting up stat.leave for everyone that gets disconnected (I have a reset system hooked up to that objective, which should reset leaving players, instead they just log back in as if nothing happened). The objective is working normally if they e.g. relog.

The weirdest thing about all of that is, that I had way more taxing maps on my realm and it seemed to work just fine. Also, I tried to reproduce this bug on another, locally hosted vanilla server with 1GB RAM and absolutely nothing happened for several hours. The game was just fine, and there was nothing in the logs that looked like it could have become a problem. also, the debug didn't yield anything of significance as well (averaging 20 ticks per second over 3 minutes gameplay).

*Here is a list of things I thought might be interesting for context:*

• There is a relatively constant count of 150-200 entities in the world (not constantly resummoned ones, but summoned once at the beginning of each round), almost all of which are area effect clouds. they all get executed upon once every few seconds.

• there is one timer objective running in the background.

• there are a few scoreboard operations done, but nothing too severe.

• around 300 commandblocks are powering the game (and like I said, only the ones needed are activated).

Sadly there seems to be no way to reproduce this crash intentionally, other than playing the game and waiting for it to crash. (Un-)Conveniently the realm seems to crash every time the game is played for a while (there were barely any rounds that didn't crash on us. I need to add that one round in this game is taking a fair half hour or so).

EDIT:

allright, we were able to narrow it down to the following commands causing the crash, in this order, in a repeating commandline:

/scoreboard players set @a amountofcells 0
/execute @e[type=area_effect_cloud,score_team=1,score_team_min=1,tag=cellMarker] ~ ~ ~ /scoreboard players add @a[team=red] amountofcells 1
/execute @e[type=area_effect_cloud,score_team=2,score_team_min=2,tag=cellMarker] ~ ~ ~ /scoreboard players add @a[team=blue] amountofcells 1
/execute @e[type=area_effect_cloud,score_team=3,score_team_min=3,tag=cellMarker] ~ ~ ~ /scoreboard players add @a[team=green] amountofcells 1
/execute @e[type=area_effect_cloud,score_team=4,score_team_min=4,tag=cellMarker] ~ ~ ~ /scoreboard players add @a[team=yellow] amountofcells 1

surrounding prequisites: there are only ever a maximum amount of one player per team. there are around 50-150 area_effect_clouds with the tag "cellMarker" present in the world during one round of the game, each starting with a team score of 0. each turn the amount of AECs that have those teamscores change, they basically increase overall. when playing with 4 players we found the threshold for the server to start acting up and likely crash after a short while of waiting to be around 80 (one instance with 84, one which was faster paced with 94) AECs having a team score of greater than one.
Again, I'd like to stress that we weren't able to reproduce this at all on a vanilla server with 1 GB of RAM allocated to it.