Check boxes locked

[CJH]

I have discovered that the check boxes for subscribing to the newsletter, and for accepting conditions, in My Account are locked. That is, they will not accept any change (if ticked, they will not untick, and if empty they cannot be checked). This means customers cannot save the form for their account, because the box for gdpr is required.

I have a live shop in 1.7.4.4 and another under development in maintenance, 1.7.6.9. Both are identical: locked. The 1.7.4.4 site used to work, and I am sure the new one did also. The only recent change in common has been to update the 1-click upgrade module, but this is disabled in both sites. I do not know the cause ... but especially, not how to fix this.

Any ideas how to fix this?

Belay that ... something is locking it only on one computer - I tried two more, and there it works. So this is an oddity presumably with the cache ... but very strange

Edited December 7, 2020 by CJH
Problem turned out to not be one ... (see edit history)

[PrestaHeroes USA]

without link it would be very difficult to give advice, I recommend using chrome dev tools, there you can look at the console for errors.  also there is PS debug mode.