Data validation problem

[Sztrogascev]

Hi!

I encountered a strange bug. I tried to create drop down list from a set of time series (00:01, 00:02, 00:03, 00:04, 00:05, 00:06, etc.) which is working fine until I type each time value in the cells manually. BUT when I try to drag down to fill in as a series, the data validation does not recognize the value when I try to type it in. If I click in the cells (which I have dragged down before) and hit enter, then the data validation accept the value.

I haven't figured it out why this is happening. Any ideas?

Thanks,
Bence