TM+VNAV is not working on stepped climbs under 10000ft, climb EPR not being set

Assumption: If my understanding is correct I should be able to use the TriStar AP with TM+VNAV modes engaged shortly after takeoff, so say for example by 2000ft, I should be able to engage both TM+VNAV and that should allow the aircraft to climb to the set target altitude at IAS250 <10000ft and IAS320>10000ft. The takeoff, climb pages in the PMS should set the correct EPR into TM system target for each phase of flight.

I am seeing several issues with TM+VNAV on stepped climbs <10000ft including -

1. TM with IAS250 does not hold airspeed at 250kts or perhaps it just gets there VERY slowly. It frequently overshoots to 300kts! (v1.0.5 release), and 270kts on previous versions

2. IAS250/3230 does not work properly if there is a step climb below 10000 ft. So say I level off at 6000ft first before climbing further, I then dial in new target alt and hit VNAV, the aircraft will not climb at all.

3. To get out of this stuck mode requires toggling AT modes so moving TM->AT->TM then the PMS suddenly sets the correct EPR for climbing with.

4. After encountering #2, when I get past 10000ft, IAS320 will struggle to achieve 320kts as the PMS unit does not set the correct climb EPR into the TM system, so the aircraft climbs at a low +500ft/min climb rate instead

So the PMS+TM+VNAV seems bugged when climbing with steps, and it's all down to the correct EPR not being set when it should be.

If I use AT mode to hold an IAS of 250kts instead the aircraft behaves normally. If I engage TM after using AT to climb above 10000ft then TM EPR is set and works correctly.

So to me there is some bug with TM+VNAV when doing stepped climbs below 10000ft. It just isn't working, and hasn't been since release.

Edited 2 hours ago2 hr by agfors
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