Termination request was submitted for a subscription but the subscription is in Graced status instead if Terminating.
The issue occured due to parallel execution of two periodic tasks: Process pending subscription termination requests and Subscription expiration procedure. As a result, firstly the subscription was put to Terminating status and a moment later -- to Graced.
Such behavior was classified as the software issue PBAS-30287 and was fixed in OBAS 4.5.7 release.
To resolve the issue, please upgrade to 4.5.7 as described in How to upgrade OBAS system to the latest available version.