is it normal for aclcheck to use up to 500mb+ of memory?

my example:
NW6sp3/BM37sp3 2G processor 1gb memory

8am Monday morning "cache allocator out of memory"
I check NRM stats and see ACLCHECK.NLM is using over 650mb of memory
I reboot the server for the first time in months and it seems fine the rest of the day

11am Tuesday morning "cache..."
I check NRM stats and see ACLCHECK.NLM is using over 520mb of memory and climbing.
Reboot server and check NRM stats - ACLCHECK.NLM is using 118k of memory - I check two hours later and it is still holding at 118k, but apparently that won't be for long.

We are getting ready to switch to a new server with 3.8 so we'll just treat it like our M$ servers and reboot it everyday until the new server is out of the test farm and into production.