Customer service was very responsive and helpful! Seems I stumbled across a little bug...it was solved right away with the next app update which was rolled out about 10 days ago or so. Tested yesterday and now the taxi charts pop up after landing :-)
Big  thanks to the SD team!‌

OK, will do. Thanks!

You may wish to talk to customer support about both those issues. They're better equipped to investigate which plate(s) exist for the airfield in question and let you know whether a taxi chart should be appearing.

Bringing this back up after a while...

I solved ‌‌the issue by buying a new tablet ;-) Got a good deal on a Samsung Tab A 10.1 which fits nicely in the mostly unused far right corner of the Cardinal's panel. But there are still two follow-up questions:

Whilst‌‌ I can enjoy the georeferenced approach plates and autozoom now (great!!), I would also like to see the georeferenced taxi charts after landing and before departure without having to switch them on manually. Situation now is that SD zooms in after landing to a scale which would be perfect for taxi guidance, but on the approach chart, so there's not much to see. Is there an option to overlay the taxi chart over the approach chart or to let SD toggle between the two (e.g. on flight log start/end)? If that options exists, I'd highly appreciate a hint how to use it. If not, I hope this will change some day :-)

On the other hand‌‌, I still use the "old" tablet on my kneeboard for when flying e.g. my club's cub. That's usually just local flights and I don't need the georeferenced approach plates for those. But how can I switch off that feature? I don't want to delete the plates from the device. But it seems that as soon as I have downloaded a plate, SD automatically wants to overlay it in flight, which tends to crash the tablet. I couldn't find the switch to turn that feature off :-( Any advice, anybody?

Thanks!!
Toni‌‌‌

Thanks for the hint about Android 5+! Seems I am having bad luck with my choice of Hardware here. Did some research on update availability and it seems Samsung never rolled out any OS update for my Tablet (they did for the 3G version, announced it for the WiFi version, but never did :-X )
However, I  checked my old Nexus 7 (from 2012!), which is really dead slow and unstable even when just surfing the web. But it has Android 6! And what can I say, the georeferenced charts are super fast on that one. Seems I have to make up my mind about which Tablet to by next :-( A Lenovo could be an option, thanks for sharing the info! In the meantime, I'll just switch off the georeferenced charts (with all VRPs and circuits in the base map, they are a very nice add-on but not 100% necessary).

‌Cheers,
Toni‌‌‌

If you cannot upgrade to Android 5 there is a super Lenovo Tablet on offer at Argos - £59.99. (I have the 8" version and it runs SD a treat).
http://www.argos.co.uk/product/6732743‌

Two of the issues above appear related to rendering the georeferenced approach charts. Please note that in Android 4.x and lower, we have to render these ourselves which is very slow and memory consuming. In Android 5 and above we ask the operating system to do it, which is lightning fast. You would probably see a big difference in performance by upgrading your Android version to 5.

Thanks for the info..,makes me think, my phone is also a pretty old S3 neo. I'll install SD on that and see what happens. If it works there, it's not a H/W performance issue ;-)
Just updated ~2weeks ago through the Google Play store. Should be the latest version, so that's probably not it.

I run SD on a Samsung S3 smartphone, so I don't think there are any specific minimum Android h/ware requirements.
However I don't use geo-referenced plates etc.‌
There were some issues with some Android devices regarding the screen refresh rate when zooming and panning but they were fixed, probably 1 year ago.
Are you running the latest SD release?
Tony N‌‌‌