RDSH mismatch Actual capacity vs Requested capacity is a thing that can happen if you refresh your Sessiosn Desktop (RDSH) pool in the tenant portal.
When you open/edit the RDSH assingment you will see something like in this screenshot.

You know for sure that the amount of desktops under the desktop tab equals to the amount of RDSH servers on your vCenter.
In that case you have some ghost VM’s. Horizon DaaS thinks there are more RDSH then there are actually on the cluster…
I found out that these RDSH servers are stored in it own table in the fdb database on the tenant appliance. So if you query that table, you will see something like: (the query is not a real time comparison to the screenshot. So the numbers can be different! )
fdb=# select * from session_host;
id | datacenter_id | goldpattern_id | desktop_model_id |
profile | capacity | allocated | network_id | protocols | date_created | date_updated
————————————–+————————————–+—————-+————————————–+————-
————————-+———-+———–+————+————-+————————-+————————-
a2f38b58-c4ad-46d8-9ff2-8b7a6983d47e | 1e7a64ee-42d6-4960-99ec-fdcd00912649 | G.1015.20 | 543f15a3-20b9-40a2-82eb-094ee34097df | 73e4e9a0-808
1-44a2-b6cd-683822a33659 | 3 | 3 | | pcoip,blast | 2019-02-11 21:48:28.115 | 2019-02-11 21:48:28.115
17e24da3-fdda-4e65-a3e2-d0798e430117 | 1e7a64ee-42d6-4960-99ec-fdcd00912649 | G.1015.20 | 543f15a3-20b9-40a2-82eb-094ee34097df | 73e4e9a0-808
1-44a2-b6cd-683822a33659 | 3 | 3 | | pcoip,blast | 2019-02-11 21:48:28.115 | 2019-02-11 21:48:28.115
e0b62b8c-c1ae-4c4b-bca9-507a25b121a4 | 1e7a64ee-42d6-4960-99ec-fdcd00912649 | G.1015.20 | 543f15a3-20b9-40a2-82eb-094ee34097df | 73e4e9a0-808
1-44a2-b6cd-683822a33659 | 3 | 3 | | pcoip,blast | 2019-01-04 23:49:48.904 | 2019-01-04 23:49:48.904
(3 rows)
In this query you see three RDSH. The last one is in this case the issue it did not refresh properly. And the system did not delete it as well.
If you delete this one form the table your assign Actual capacity vs Requested capacity will be equal again.