Yeah, we can have non-legal opinions about this, but your situation presented gets "iffy". Might be a good idea to check for any help you can get with your base separation services.
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My non-legal take on this:
A person separating service has 180 days to re-establish their permanent residence in their original state...or in some new state any time in that 180 day period. Thus you could be considered to be locked in as a TX resident .....unless you/your family decides to remain in UT beyond that 180 days.
BUT....For you, the military-separating person, the work in CO will be as a Civilian...and any time you physically work within CO, that pay will be subject to CO taxes...as a CO non-resident....unless you decide to permanently move and live in Colorado. The civilian W-2 income doesn't become TX income, subject "TX non-taxes" until you physically reside and physically work within TX.
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Not sure UT has a stake in it unless you/your family continues to live in UT beyond ~6months (but don't push your time there) . IF other spouse works civilian job in UT, I have no idea if the MSRRA lock as TX resident for that spouse's W-2 continues for up-to 180 days or not. That's way beyond what we might be able to deal/guess at in here.
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Read thru all of the following. It may have some helpful links for more expert advice:
Where to Live After the Military | Military OneSource
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Other Note..Only the "Title" of your question has limited # characters...the additional information below the title....and comments don't (well might be some limit, but we've seen a couple folks go on for a thousand or so words, so it would be pretty huge) Don't write a book though...no one will bother reading it.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
