Experiencing the same exact issue.
The date acquired is plainly visible in the form entry too, but nonetheless submitting the same date into the text box and hitting "Continue" does nothing, the widget basically just reloads.
Sure thing, let us know here or there (both?) if any workarounds help you.
I myself will likely do the suggestion where you pull the data (provided via "magic" api call to fetch your investing data) out of the filing and then re-enter manually as a lump sum P/L which doesn't require any dates.
Just procrastinating actually trying that cause I'm frustrated as hell with TurboTax rn, I doubt the issue is on the end of several different investing brokerages' API's (I was a Stash customer in 2020, aka Apex Clearinghouse Corporation is my brokerage where I fetch data from).
Plus this api fetch worked 100% perfectly last year. Granted I had a lot more activity this year, but none of it was any new "kinds" of activity, so I don't understand why it's any more complex to handle this year than last year. I suspect the TurboTax development team(s) introduced a software bug this year that causes this issue.