Router restarts when running a Tor relay inside my network

[Pixel5]

Hello People,

 

i have been running a Tor relay on my NAS for about 6 months now and since about 3-4 months my router just randomly restarts, my ISP has no idea what it is they replaced all the hardware and everything seems fine.

 

now i noticed that as soon as i turned off the tor relay and closed the ports there were no more restarts, first i suspected my ISP is trying to get my data usage down this way as the Tor relay itself had about 6-7TB of traffic per month plus what is normally use myself.

 

but the restarts also happen when only very little data has been transferred so i really have no idea whats going on and why it is happening.

 

My router is a Fritzbox Cable 6490 with Firmware 7.01 the restarts happened more rarely with the old 6. something Firmware but it still happened.

Does anyone have any idea what could be causing this?