Our testing here shows the same thing. This has been passed along to our Development Team for further review.
At this time, there isn't a work around other than renaming the Tab to not include a comma.
Lead Solutions Consultant
THX, it was incidentally that I became such sheet from an external source.
Incidentally too I've found a little error within help (time and date pattern)
d Day in month Number 10
F Day of week in month Number 2
at first the description of 'F' was mysterious for me, but I think it's a little 'c&p' accident.
Perhaps can you passed this along to your help author too?