Flexget 3.1.51 - error in loading plugin ... notifiers.telegram

Hello

Since upgrading to version 3.1.51 I notice the following error regardless on the command I try to run on the flexget.

Disabling in config.yml any referrence to telegram does not help either, even after system restart.

Host system: raspberry pi 3B+ with latest raspbian, python 3.7.3

2020-04-23 08:46:10 CRITICAL plugin Exception while loading plugin flexget.components.notify.notifiers.telegram