Has it lost the agility it had before with some update?

[Nucleorion]

Since a few weeks ago, with some update, Thunderbird often freezes. For example, when I send a message, before I could continue working while the message was being sent, now it freezes for 4 or 6 seconds, and I can't do anything but wait.

Has it lost the agility it had before with some update? Are you aware of this? Or is it just me?

Thanks