This is a quick one.  My attention was recently brought (thanks Simon) on a relatively recent comment (25 Nov 2025) in Bug #103672 - Binlog compression transaction payload event exceeds max allowed packet :

The underlying server bug was fixed in 8.0.34 in BUG#33588473. The server now falls back to writing the transaction without compression, if the compressed size would exceed 1 GiB.

So Binary Log Transaction Compression is safe since MySQL 8.0.34.  But this also means that it is unsafe before, as also clearly mentioned in Bug #103672 :

It is true that an 8.0.33 server (or older) will produce a corrupted binary log and that replicas may have to recover from backup. It would be better to document this clearly and to advise to not use compression on 8.0.33 and older.

However, even if updating the documentation is mentioned in the above quote, my quick check did not find any reference to the risk of using binlog compression before 8.0.34 (including in the documentation of the global variable binlog_transaction_compression).  I thought this deserved wider knowledge, hence this post.