I primarily use it on my tablet also, with the phone as a backup. I have a Samsung Galaxy Tab S 10.5 which is what I normally use. A month or so ago, I noticed that when switching to the approach plates, Home>Charts> Whichever Binder> plate it was just taking way too long to make the transition. Could be 30 seconds or a minute to get the binders, and then Another minute to get the detail thumbnails within the binder and then another 30 seconds for the approach plate itself to come up. Way too long and unacceptable. My phone is slightly faster, but still too darn long.
I called Garmin and went round and round with them and then finally they tried it out on their tablets in the office and agreed that there was some problem and they would "send an email to the developer". I guess that speaks to the level of support that Garmin is giving their product.
I was just trying to find out if anyone else was having the problem and could get them to call Garmin and complain so that maybe they would actually do something. You might try this number for Aviation Product Support 1-866-739-5687
And yes, before you ask, I've done everything I can do including cache, uninstall, reinstall, and I even did a factory reset.