Strange tempo behaviour importing MS2 files to 3

Here's a silly little tune for a stage production. Everything worked fine in MS2, but I had to get cocky and import it into MS3.
In the attached file, the intro (Measures 1&2) should play at 88 bpm. It works fine in MS2. Importing the file into 3.05 or 3.1Beta introduces some strange behaviour. The opening measures play at 120 bpm. The tempo marking at measure 3 and subsequent tempo events work fine. I've tried deleting and re-inserting the initial tempo, but it doesn't help.
It gets stranger:
If I delete and re-insert the opening tempo to 80, it works fine, but if I change it to anything else, it goes back to 120.
70 bpm plays as 120
160 bpm plays at 120
I'll attach versions saved in both MS2& MS3 in case you can see something that the program is doing to the files.