Mapsforge hill-shading bug for Android version >=8.0 and Orux version > 7.3.4

[svrider]

Hi,
This bug has already been mentioned in this post from another user (https://oruxmaps.org/forum/index.php?topic=21242) but it became no answer so I will explain the issue more in detail.

On my phone & tablet, the Mapsforge built-in hill-shading is not displayed at "usable" zoom levels, only for low zoom levels (9 and lower). So I decided to make an exhaustive test campaign :

I have tested my two "real" devices : Galaxy Tab A10 & Galaxy S8 running with Android 9.0
And also several devices with the Genymotion emulator : Galaxy S3, Nexus 5, Amazon Fire HD 8, Galaxy S9, running on Android versions 4.4, 6.0, 7.0, 7.1, 8.0, 8.1, 9.0.

I have tested several versions of Oruxmaps : 7.3.4, 7.3.7, 7.4.22, 7.5.9beta38

I have enabled Mapsforge built-in hill-shading, and disabled Oruxmaps hill-shading :
"Maps settings/Mapsforge settings/Apply hill shadows" Enabled
"Maps settings/Apply hill shadows" Disabled
I always use the "Default mapsforge theme" (hill-shading is enabled by default : <hillshading/>)

Hereunder the status :


Hill-shading is displayed for Oruxmaps versions up to 7.3.4 or for Android versions up to 7.1 
But for Oruxmaps versions higher than 7.3.4 and for Android versions 8.0 and more, the hill-shading is NOT displayed for zoom level higher than a threshold that is device dependent (8 to 10 in my tests). For zoom levels below this threshold, the hill-shading is displayed normally.

Note : the behaviour is the same for all maps I have tested (Openandromaps (v4), Mapsforge site maps (v3, v4, v5), self created maps (v4)).

Something happened between Oruxmaps 7.3.4 &7.3.7 and/or between Android 7.1 & 8.0

@orux : would it be possible to check if there is an explanation to this behaviour ?

Thanks
Daniel