Alphanumeric Key detection Problem

Key detection is calculated by the software and the accuracy depends on how good the algorithm is written. That means that when you change software and re-analyze the tracks some of the key results will differ. It does sound weird that all keys have changed though.

Tip: Choose your key detection software and use only that one, do not switch between different apps. They all have their flaws, but if you use the same one on all of your tracks you will have less problems with key clashes etc. since you use the same algorithm.

True, every software tends to assign the key according to its analysis algorithm... and there is no absolute one.
I've been using this for quite some time:

http://www.ibrahimshaath.co.uk/keyfinder/

It offers you the possibility to analyze "in general" a track, or to do a thorough analysis.
If you choose this option, you will notice that the key within the track changes.
This is because the program must make an average of the frequencies it detects by combining drums, bass line, pads, voices,
etc...
The advice to always use the same program to detect the key of a track is absolutely right.
Choose "your" PROGRAM ... it will not be perfect, but any error will be constant.