time signature after pickup bar strange behaviour

easiest way to reproduce:
- take the Reunion demo file
- open time signature palette
- drag 2/2 time signature to the first regular bar (the one after the double bar line, counting the first bar as a pickup bar)
result:
- time signature is not shown
- all effected bars will get 4/4 time with effective length of 2/4, which is wrong

though if you put the 2/2 time signature to any other bar, the result is correct

maybe this is the same as any of the other bug reports about disapearing time signatures; don't know