adjustTime(number) problem when adding seconds

As you can see, I added some test code to the existing example TimeTeensy3. With test set to HIGH you can see that the clock doesn't advance beyond 5 minutes or so.

With test set to LOW the clock advances OKE.

Seems that there is a problem with adjustTime?

Attachment 20834 Attachment 20835

>>> Added code <<<<
boolean test=HIGH;
if (test) {
adjustTime(120); // Does not work beyond 5 min. when test=HIGH
} else {
setTime(now()+120); // Works perfect when test=LOW
}

I forgot to tell that this is done on a Teensy 3.6.

The example sourcecode is on Github examples/TimeTeensy3/TimeTeensy3.ino

Hello,

with adjusttime() you set timelib object but not the RTC on Tennsy 3.x.
In setup() you have set syncronisation of timelib with teensy-RTC by "setSyncProvider(getTeensy3Time)". Default time for sync is 300 seconds (5 minutes). You can change this by "setSyncInterval(seconds)".
So after 5 minutes your before adjusted time in timelib (+120) ist resyncronised with RTC an set with value of RTC.
Bear in mind timelib and RTC are two independent objects.
Of course you can also adjust RTC with "Teensy3Clock.set(t)".

Thanks for the great and quick reply.

That explains a lot!!