Acrobat DC freezes/crashes when trying to add text in one spot on the document

I had a DC Pro account for several years.  It always worked fine (iMac Catalina).  I let the subscription lapse.  A month later, I renewed (same iMac but Big Sur).  Today I opened a contract that I had created under the old subscription.  I used Fill/Sign to add some text in several locations.  When I got to one spot in the contract, as soon as I clicked where I wanted to add someone's name, I immediately got the Beach Ball of Death.  The program froze and eventually crashed.   Subsequent attempts produced the same result.  I Forced Quit.  I uninstalled and re-installed with the same outcome.  I have no idea what is going on and don't know what to try next.  Any ideas would be appreciated.