Navigation arrow color changed to green?

I called Garmin Italy today. They have no records of this issue so far. They suggested me to free internal memory and then reinstall maps on Garmin Express. It's still updating. I'll keep you posted.

I've made a picture of my navigation screen below (I use the Dutch language settings). I've added an arrow showing the direction of where the navigation route requires me to go first. The black lines around the green line are a bit heavier for the navigation direction, but it is very hard to see. The route requires me to drive around a block of houses and then go left (in this screenshot around the red cross in the lower left corner).  

Are you using any Connect IQ data fields?

Yes, I have the "Komoot" and the "Strava Routes" app.

Further, I have the following data fields installed:

- Heart Rate Zones Chart

- Power graph

- Live Peak Power (MMP) Graph

- Power Peaks

In the not installed section of Garmin Connect:

- My EDGE

- SPH Graph - SPHGraWH

- Charts

- vPower

Here's a screenshot of my situation. I have no Connect IQ datafields installed

as suggested in this topic https://forums.garmin.com/sports-fitness/cycling/f/edge-820/196892/issues-with-colours-of-the-navigation-maps/962418?focus=true by another user I reinstalled/updated the maps on my edge 820 via the garmin express desktop app.

I'm now running:

- standard basemap, NR

- Garmin Cycle map EU, North East, 2019.10

- Garmin DEM Map Eu; 2019.10

- Garmin Geocode Map EU 2019.10

- Garmin Cycle Map EU, South West, 2019.10

I've only did a quick test while commuting but this seems to have resolved the problem 

I will be able to verify this during a ride this weekend

Thanks for your answer! I've also installed the maps again. At first glance it looks like the colors of the map are back to normal. But I have to check them during an actual navigation as well. 

update: I completed a ride yesterday and everything worked as it used to. So updating/reinstalling the maps via Garmin Express is the solution in my opinion.