Premiere 15.1.0 cannot open a team project previously created on 14.8.0 - help!

We have been working on a team project using Adobe Premiere Pro 14.8.0. A team member recently opened the project on 15.1.0 and shared changes, which forced the rest of us to upgrade Premiere to 15.1.0 in order to open the project.

Now, when any of us open the project, Premiere crashes. We get an error dump (shown below).  This is a very serious issue for us as this is a major film production. Please help.

Process:               Adobe Premiere Pro 2021 [3757]
Path:                  /Applications/Adobe Premiere Pro 2021/Adobe Premiere Pro 2021.app/Contents/MacOS/Adobe Premiere Pro 2021
Identifier:            Adobe Premiere Pro 2021
Version:               15.1 (15.1)
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           Adobe Premiere Pro 2021 [3757]
User ID:               501

Date/Time:             2021-05-04 14:36:22.736 -0700
OS Version:            Mac OS X 10.15.5 (19F101)
Report Version:        12
Bridge OS Version:     4.5 (17P5300)
Anonymous UUID:        A93A3CF9-F0BB-E564-CF97-29A537FA4E06


Time Awake Since Boot: 1300 seconds

System Integrity Protection: enabled

Crashed Thread:        81  Dispatch queue: com.apple.root.utility-qos