Hi!
I would say it is a bug, but probably somewhere it is written.
So my observation is about time input. I rightclick on ruler bar and select Time Format. Then I choose Offset tab and activate “Set Time of First Sample” option. Now the time input field is available showing me “0 s”.
Okay, I click on it and it transforms to “0 _ h _ mn _ s _ ms”. Is it correct? No! Because if I click on zero, it is selected and when I start to write digits, it replaces existing zero with first digit I pressed, then next digit is placed at the place I wrote underscore symbol. So, if I enter 22 (it’s 10 PM) for hour, WaveLab received 2 (space) 2, because first symbol should be “+” or “-” just to have possibility to enter offset.
So I think that first symbol always should be “+” and selected zero should be at next place before “h” letter. If someone needs negative offset, he will go to sign position and change it. I’m sure 99% of situations we need positive offset. I also am sure that 90% of readers here don’t use ruller offset change 
Sorry for this disturbance. I just work on large files third day and every time I’m going to set time for each recording, I enter it wrong, because entering 22 results in “2” where a sign needed and second “2” entered for hour. In a result WaveLab omits them both and I have zero hours.
P.S. About large files. I already wrote in SpectraLayers category. If the length of WAV file is 2 GB or more, markers created in WaveLab aren’t shown in SpectraLayers. For smaller files it works perfectly! Thanks.