[Bug] Multi-Tick track entries on wrong day

[CRTified]

Hi,

I have noticed a small bug while creating a new track and filling it for the last two months:
When having a multi-tick track, it is not possible to enter a tick exactly one month ago.
So if you want to enter something on the 19th January, while it is currently the 19th Februrary, it will not appear in the january, but instead in februrary.

To reproduce, do the following:

1. Create a new Multi-Tick track.
2. Scroll back exactly to the date a month ago
3. Try to make a tick there (Nothing should happen)
4. When reopening the App/Showing details and returning to the overview, the tick is placed "today"

I was able to reproduce the bug on two devices. Both devices used version 1.4.2 from F-Droid.

Cheers
Amarandus