Playback Tempo & Volta

Hi
I've just updated to MS 4.4.0 running on a Windows 11 PC and have encountered an issue with playback of a file I created with an earlier version of MS 4 (I think).

To cut a long story short, a tempo change to the Second time bar now effects the tempo of the First time bar. VoltaTest.mscz attached.

An effective workaround is to repeat the initial Tempo definition at the first note of the First time bar. Playback is then as I intended. VoltaTest-fix.mscz attached.

I had expected the initial tempo to be maintained until the Second time bar was encountered. The workaround is straightforward but it toook me a long time to pin down the problem. So:
• is it a bug?
• have I done something silly?

Regards
Brian