Calendar / Datepicker - February bug?

Questions
1

It seems to be a bug in the months of February, please look the video:

https://drive.google.com/a/embradic.com/uc?id=1bxAuk0kVdeU5Bkuvd1ddsRv149-idhwx

Am I right?

2

https://framework7.io/kitchen-sink/core/?theme=md в китчене все нормально.

3

Here the same problem occurs (only in February):

http://bit.ly/2VvTPEW

4

Same problem here. The bug also occurs if you select the first day in February and last day in March.

Additionally, it occurs if you select the first day in October and last day in November!