I tried to move https://en.wikipedia.org/wiki/Vatican_Apostolic_Archive and its talk page, and the first time it failed:
To avoid creating high replication lag, this transaction was aborted because the write duration (3.6277875900269) exceeded the 3 second limit. If you are changing many items at once, try doing multiple smaller operations instead. [XcCTRQpAAEEAAHaYvp4AAAAF] 2019-11-04 21:08:29: Fatal exception of type "Wikimedia\Rdbms\DBTransactionSizeError"
If the first message is going to be displayed, with an explanation, the second, with the actual exception, isn't usually needed. Also, how could it have been too long if it worked a few seconds later?