This is the issue originally discovered in this topic
, made into its own topic as it appears to differ from the one the OP describes.
Replication is possible by executing the following command rapidly, using a keyboard shortcut:
Write [Blue] 'Beginning test' to log
Say, '2' (and wait until it completes)
Say, '4' (and wait until it completes)
Write [Blue] 'Ending test' to log
Doing so leads to very few commands actually finishing, as indicated by the lack of "Ending test" entries in the log, and "Stopped command, ''" entries when stopping all commands.
Testing in v220.127.116.11, pressing the keyboard shortcut 5 times in roughly 1 second will result in only one command finishing correctly, with only one "Ending test" entry in the log, and four "Stopped command, ''" entries upon stopping all commands.
This hasn't come up in almost ten years, so, I'm not going to classify this as an emergency just yet.
As there is probably little point to having TTS play over itself, especially in rapid succession, I don't think anyone minds if this is categorized as "noted".
EDIT: Fixed in v18.104.22.168