Insufficient port capacity to load unit

[Von Weber]

Latest patch. Human vs human game in hot seat mode.
Road to Leningrad scenario. First soviet turn.
Depleted and isolated soviet unit( 48th rifle division) with transport capacity 551/535 can not be loaded in Ventspils in a naval transport mode. Attempting to make movement , clicking on a sea hex, comes a pop up message:" Insufficient port capacity to load unit"
Port is not damaged and has 30000 load/unload points.
Single manpower in the port-town is damaged, although nobody bombed it
Shipping around port hex is heavily contested due to German interdiction, the interdiction ratio is about 3:1 (39:11)
But can easily move ( sure interdiction will sink some of my ships, but move will occur)with a naval transport to Ventspils any unit from any soviet port. But I can not move unit out from Ventspils
There are 20 transport ships in pool.
Any ideas

[Wiedrock]

I think the message should say: "you do not have sufficient SMP/MP to board the ship".

[Von Weber]

So the unit has lost some movement points in combat at Axis ground phase turn and now it has not enough SMP points entraining or for embarking to the ship.
I found another unit that can not load on train by the same reason, lost movement points during retreating in Axis ground phase.So the unit can be routed during Axis ground phase, rallied during Soviet logistics phase and has some spent movement points and be not capable for Strategic movement. Is it correct?
How to explain that after the combat in Riga two HQ and combat unit retreated to the same hex but spent and have left different SMP and MP ?
1.Baltic M.D. has 0 SMP and 0 tactical MP
2.NW Aircommand has 200SMP and 25 MP
3.22nd Nkvd Mot. div has 200SMP and 6MP

Isolated and depleted division in Ventspils from my previous post:
46th rifle div 0 SMP and 8 MP

[Wiedrock]

1. In GC41 the M.D.s always have 0SMP/MP, I suppose that's a general rule and what you see.
2. That's the normal 200SMP everyone gets (besides the M.D.s ...and maybe frozen ones), the 25MP is the max you can have as a Soviet for your MOT untis in June of 1941.
3. The 200 again, normal. The MOT heavily rely on Ready vehicles and Fuel to determin their MPs. They do not have a high "min MP" limit, I think it is 1MP.
4. Inf/(+I think Cav) always gets 8MP at least.

Generally, each unit rolls its own MPs. It's completely separate rolls (several) for each unit.