I do see some mod-perm calls. I cannot be certain if they are related though.

do we have a release of mod-at with MODAT-50? If so, can we get it updated on the BugFest env?

The cache miss should cause a call to mod-perms. Do we see related timing on mod-perms? It might be helpful if we can release and deploy 's fix to mod-authtoken so request id can be passed properly and show up in the log.

It appears that yet again mod-authtoken figures prominently in this request. this line:
468917/circulation;875910/loan-storage RES 202 278078 mod-authtoken-2.2.1 http://pvt.lb.bf32.folio-eis.eu-central-1:8051/mod-authtoken/loan-storage/loans?query=(userId=a7f483c5-8cd4-46cf-9a56-1430ec2514cc%20and%20status.name%3C%3EClosed)&limit=1

takes 279ms and this line:

468917/circulation;829541/holdings-storage RES 202 192816 mod-authtoken-2.2.1 http://pvt.lb.bf32.folio-eis.eu-central-1:8051/mod-authtoken/holdings-storage/holdings?query=id%3D%3D%28%22dd00837f-d9be-4357-8f54-a9d2b19770d9%22%29&limit=2147483647&offset=0

takes 192ms

of note here is that mod-at does not ALWAYS seem to take a long time even for this same module. I would hypothesize a cache miss or some other cache behavior is causing this issue.