Xfinity Buy one get one free promotion disappeared in 6 months

I purchased a new Xfinity connection in December 2024 under a "Buy One Get One Free" (BOGO) promotion, but I have noticed two issues upon reviewing my past bills:

1. I have only been receiving a $20 discount each month instead of the expected $30.

2. The promotional discount ended after 6 months, whereas my understanding was that it should have continued for 12 months.

Is this common?