Emails not decrypting properly from same person

[BJ Strange]

Recently I've started having trouble with decryption. Some emails will decrypt and show the contents while others say they are decrypted but do not show the contents. If I view them on another client I see the content. I've attached images showing the differences as reported by Thunderbird. What can I do to track down this problem?

[BJ Strange]

The good email image

[Patrick Brunschwig]

This type of problem has usually two possible reasons:
1. An incompatibility with some other add-on
2. A corrupt XUL store

1 is quite self-explanatory.
For 2: quit TB, then delete the file 'xulstrore.json' in your TB profile directory

[BJ Strange]

Thanks for getting back to me. The only other addon was the CompactHeader one. I disabled it anyway and restarted but had no change in behavior. I deleted the file as indicated as well with no change. Any other possibilities?

[BJ Strange]

Also I've noticed it works consistently on one pc but not on the other. The working one is thunderbird 52.9.1 with enigmail 2.0.8 and the failing one is thunderbird 60.7.2 with enigmail 2.0.11.

[Patrick Brunschwig]

Then it may depend on the structure of the messages. I made some changes in Enigmail 2.0.11 that restrict decryption/display to some degree. If you attach an example message that won't display, I can tell you if that's the case here.