Thunderbird opening pgp encrypted message very (I mean very) slow

Since I migrated to Leap 16.0 I notice that when I try to open an encrypted message in Thunderbird it takes almost one minute to see that massage in TB.
When I save this message to a file.eml ant then open it in terminal

gpg --encrypt file.eml

it’s opened immediately.

PS. I tried to find a problem with chatgpt but no avail. We checked all software and configs.