Similar issue here: I have an actual NodeRed and Telegram Node installed about 3 months ago at a raspberry pi. Everything works ok, but after - lets say - a day the receiver stops working.
I have only one receiver and one sender in all of my flows, and while the receiver fails, the sender is still ok. No syslog error messages. Any ideas?
It works so, that I send this messages (commands) that are then interpreted and answered.
In Telegram on my mobile I see 2 marks like "read/received" (always). It is a group with the bot and me.
Then the raspberry receives it does actions and sends me a confirmation back. I also have some notifications, that it sends to me on a time-based schedule, without me sending a command. The time-based always works (so I know that the Telegram sender works) but the confirmation and the action stops after some time ( half day, a day or so)
Yes I am sending the messages, let me say "/?" that is interpreted as a command.
I use the "Telegram receiver" not the "Command" anymore, because I suspected confusion by so many receivers, Now it is just one left and a "switch node" after it. Is that what you mean?