This:
/interface lte apn
add apn=internet.telekom use-network-apn=yes
May be the issue, you should edit the entry setting use-network-apn=no
See:
http://forum.mikrotik.com/t/lte-apn-with-fix-ip/139907/1
See also, it should be possible to disable it via GUI too:
https://blog.linitx.com/mikrotik-lte-how-to-configure-apn-settings-part-2-use-network-apn-issues/