Why does TT show HSA distribution as taxable if one spouse doesn’t have hdlp plan?

We must be talking about two different things. It does not matter if your spouse did not have HDHP coverage so long as your spouse did not contribute to an HSA. 

And by distribution, are you talking about a 1099-SA? This has nothing to do with the spouse being covered or not.

Instead, a distribution on a 1099-SA might be taxable if you did not indicate that the distribution was all for medical expenses.

To help me out, tell me if 

1. you had a 1099-SA

2. what its amount was in box 1, and

3. on what line on the 1040 (and Schedule 1, 2, and 3) does the distribution appear?

In addition, did you get a message that your spouse had a lapse in HDHP coverage?