Nope. There's no way of viewing past CR TC activity. Only way you can kind of view it is by viewing your Rewards Statement and calculate it based on gaming earning rate and spend earning rate to get a general idea and estimate. Or, if you hit one of the daily bonus limits, you will usually get an email for it a day or 2 later.

You most likely got it from either one or more of the multiple bonus earning events from last year (2x/3x etc, QFR-Quest For Rewards, Earn for 2020, etc).