I am running the latest version of DVD Profiler on my pc and have uploaded my collection , waited 30 mintues and then used the download feature on the android app.

When i use the browse button on Android DP i can see the tags i created on my pc but they show 0 entries. I doubled checked the PC and i can filter the tags without any issue.

I created a new category on the PC for my Blu-ray titles and used the "unique numbers" option and my BR titles do not show up under "owned" and that is the way i want it. The android app uses the "All" category to browse and my BR titles do show up on the PC under ALL so it should on android and therefore list my tagged titles.

On the Android go to settings and under display i have enabled the " All Collection Category " ( shows entries from all categories ) and this works to see both the Owned and Blu-Ray category when looking
at the profiles but not with tags.

Since my post i've tried the repair utility on my PC and then re-uploaded my database and then downloaded it again on the android. No change

Not sure what you consider a sub collection. I have the 4 default categories ALL,ORDERED,OWNED & WISH LIST and i created a 5th one that i've name BLU-RAY and because these have there own unique numbers and go from 1 to 279 i didn't check the option to add this new category to the OWNED category as i didn't want two #1's and two #2's etc.
On the PC  i use filters to see titles i've tagged but on Android see no filter that will allow me to filter tagged titles as done on the PC. On the android i can sort by the following :

Title
Media Type
Release Date
Production Year
Rating
Runtime
Genres
Country of Origin
Collection Number
Purchase Date
Review
Random Order

And if this is what you consider a filter than none of these filters will permit me to see titles i've tagged
for various reasons.

A separate issue is again with tags. I had a tag on the PC version that i renamed and then uploaded my database and once downloaded via Android it shows the old tag name and the new tag name as if they were two different tags but there one in the same.