What is your default map (A in the help document below).
What is your overlay map (B in help doc below).
https://support.myrouteapp.com/support/solutions/articles/12000074551-manual-map-layers-
What happens if you create a new route - do you experience same issue?
I recently posted an issue with HERE map loading very slow (will appear blurry as it slowly loads). The suggestions were to use a different "overlay" map such as Google maps overlay. That fixed my issue.