This is pretty much as intended. What would expect to happen differently, @turt2live?
1 less enter, also not 2 code blocks.

That should probably just be a continuation, instead of a whole new block.
Interestingly gitter and slack have each adopted quite a different approach to multiline messages - gitter has a 'composer mode' (essentially something that stops enter from submitting until you disable it) and slack has a 'snippet' editor - a whole separate modal editor for editing multi-line code blocks.
I would prefer Enter to always send the message and Shift+Enter to insert a new line. It's quite a common pattern in desktop messengers I used before.
fixed in matrix-org/matrix-react-sdk#1890
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Interestingly gitter and slack have each adopted quite a different approach to multiline messages - gitter has a 'composer mode' (essentially something that stops enter from submitting until you disable it) and slack has a 'snippet' editor - a whole separate modal editor for editing multi-line code blocks.