Dear Jacob,
I have exactly the same issue (V.4.0.16 of FTX Central), even withouth Germany North/South installed. This is a screenshot of central/west germany in which you can see the black tiles. Aircraft is located at Frankfurt (EDDF).
I have verified the LC EU files and everything seems fine. Issue is still present even withouth REX.
Installed ORBX products in this region:
ORBX Global
ORBX EU LC
Cheers,
Nik