Memory limits for Tor process

Hello.

I’m running Tor with MaxMemInQueues 1 GB for many years.
But today I noticed that Tor process uses 2 GiB of RAM.
What kind of data Tor may store, which is not limited by MaxMemInQueues?
Is it related to latest attacks?
I guess that increase in consumed memory could have happened today at 01:00 UTC, but I’m not sure, I’m not monitoring it directly.

From this topic: [tor-relays] relay memory leak?

Selection of 75% of total memory is a strange decision.
Tor easily exceeds 1.33 (1 / 0.75) of MaxMemInQueues.
My record is 3.5 GiB working set with MaxMemInQueues 1 GB.
For selecting of the best value for MaxMemInQueues it is better to know at least approximate formula for maximum total memory consumption of Tor process.