The flow I'm using for testing now looks as follows:
[{"id":"81eeedb9ca739de9","type":"telegram sender","z":"2ee5b5dc.d3b792","name":"","bot":"c1d85a8f3619940c","haserroroutput":true,"outputs":2,"x":400,"y":1120,"wires":[["1c2de620d7b4be26"],["1c2de620d7b4be26"]]},{"id":"133ef30eabe7b34c","type":"inject","z":"2ee5b5dc.d3b792","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"content\":\"Testnachricht\",\"chatId\":123456789,\"type\":\"message\"}","payloadType":"json","x":370,"y":1060,"wires":[["8b6a0143d472ba0e","81eeedb9ca739de9"]]},{"id":"1c2de620d7b4be26","type":"debug","z":"2ee5b5dc.d3b792","name":"debug 1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":620,"y":1120,"wires":[]},{"id":"e8afbf605c42a3be","type":"catch","z":"2ee5b5dc.d3b792","name":"","scope":null,"uncaught":false,"x":380,"y":1180,"wires":[["85716bcf2f57373e"]]},{"id":"85716bcf2f57373e","type":"debug","z":"2ee5b5dc.d3b792","name":"debug 2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":620,"y":1180,"wires":[]},{"id":"8b6a0143d472ba0e","type":"debug","z":"2ee5b5dc.d3b792","name":"debug 3","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":620,"y":1060,"wires":[]},{"id":"c1d85a8f3619940c","type":"telegram bot","botname":"Status","usernames":"","chatids":"","baseapiurl":"","updatemode":"none","pollinterval":"300","usesocks":false,"sockshost":"","socksport":"6667","socksusername":"anonymous","sockspassword":"","bothost":"","botpath":"","localbotport":"8443","publicbotport":"8443","privatekey":"","certificate":"","useselfsignedcertificate":false,"sslterminated":false,"verboselogging":false}]
There is only an output from debug 3 with the message going into the telegram sender node.
The telegram sender node always shows "connected" regardless if the Token is correct or not.