By default when you use HH:MM it's a TIME type of format
Format is TIME :
Format is DURATION :
01/01/2019 + 25:00:00 = 02/01/2019 01:00:00 with the TIME format.
01/01/2019 + 25:00:00 = 1043209:00:00 when using the DURATION format.
Conclusion : try using HH:MM:SS to avoid futur format problems with ...