Perhaps the best hint for the real build date is the date of calibration: 03/08 2016.
Not updating all parts of the software (incl. Boot Loader) to the current version looks somehow simply
strange.
(Every silly PC is able to perform a BIOS-Update...)
Regarding the bugs:
I have transformed your text into the following checklist (hoping I got it right):
1. Slow response to controls like the Vertical positioning control.
2. Occuring RMS voltage reading measurements on channels with no actual inputs and even ground-coupled.
3. Measurements Freeze bug that causes all measurements to stop updating after some random time when Math is in use.
(Using the Statistic "on" and Stat.Sel. "difference" settings to keep track of the number of updates before they stop).
4. Math horizontal offset/scaling error at 500 ns/div when in Average acquire mode and some two-channel Math function is being used.
It is difficult for me to answer the first point. I don´t know, how the scope has responsed with former software versions.
The other bugs will be checked. After this "I´ll be back" and report.
(To be honest: I doubt that the Boot Version 0.0.1.4 had solved a single one of the known bugs.)