When using the call number block, then my phone behaves as if I'm calling a real number. With the dial number block I manually have to press the call button, but it'll also calls the number and does not open the settings.
The USSD block seems not to work at all. It looks like
this and
this, but only shows the following in the log after starting it:
2019-02-06 23:59:41.223 INFO 47995@1: Flow beginning
2019-02-06 23:59:41.224 INFO 47995@2: USSD request
2019-02-06 23:59:47.950 INFO 47995@2: Stopped by user
Only if I copy the code manually into the dial field, then the settings are opened.
Observed with LineageOS 15.1.