Hi, our OpsCenter is having the same issue as describe here. We opened a Case # 06756537 on June 13. So far support and I weren't able to get this control. We did some config file tune up to limited the issue, but the only work around so far is to run a "task scheduler" to defrag DB.
Our TMP file is 12GB, isn't as big as your, but Symantec thought we are the only customer facing this issue they can't replicate in their lab. Current answer is "From what backline told [...] there is no set normal size of operation"
I'm glad we have another customer facing same issue. I'll report this to my case ID.