There used to be spam defense log in All Recent Account Activity area of the user in ACP:

After update to the latest IPS version, this log is not shown anymore. Spam Defense is enabled. All spam defense logs are shown under /admin/?app=core&module=moderation&controller=spam&do=serviceLogs though.

 

Thank you for bringing this issue to our attention! I can confirm this should be further reviewed and I have logged an internal bug report for our development team to investigate and address as necessary, in a future maintenance release.