Advice for baking STM32 ICs

[TwoArmsTwoLegs]

I bought 50 STM32L07 ICs for a small production run.
about half of the boards i've been making have been failing in one way or another.
I've been trying to eliminate potential sources, because it's getting a little silly seeing so many beautiful devices lining my rubbish bin.

I've eliminated cheap T-962 reflow oven as having too inconsistent a heating pattern.
Instead I'm using a temperature controlled hot-plate at 210 degrees C.

I'm trying to eliminate moisture in the ICs as being a source of failure.
Is moisture something that has been an issue for anyone else?
Is it usual that moisture / overheating might cause one function of the chip to break, while leaving the rest unaffected? or is it more all/nothing normally?
Does anyone have any advice for baking the ICs? I've done 9 hours at 125 degrees C for some of the chips. but I'm not sure it's worked.
The chips are recognised in boot mode and program correctly, but both boards, the i2c device doesn't seem to be working.
Admittedly I baked them in the suspect reflow oven, though they were shielded from direct IR with a black PCB.
Maybe I overheated them bile baking?

I understand that the ICs are level 3 moisture sensitive.
The indicator card is indicating the that ICs have been exposed to too much moisture for that level.

Do I need to even worry about moisture if I'm soldering about 90 seconds from room temp rising to 210 degrees?

everything *can* work. But recently none of them have been working in full. and I'm really struggling to see why that might be.

Any thoughts at all would be very appreciated.

Any advice about good alternatives to the T962 reflow oven? I've not yet found anything at a manageable price point.

EDIT: Also Chip storage! I forgot to ask. Is it ok to pop unused ICs into a tupperware with a couple of large silica gel packets? or do I need some more serious equipment?

[JCVMad]

También usé horno de reflujo para hacer un PLC con un 2560 de arduino. No me gustó como quedaba, aunque la solución es usar pasta de soldar de baja temperatura (160º).
Al final usé una pistola de calor para soldar componentes..

[hobbya]

Although the chips are not moisture-proof, I have not heard of any failures due to moisture trapped inside the chip. I do not keep my development boards within enclosures and I have not encountered failures after prolonged storage. Since your boards are partially functional, I suggest to investigate if the problems were caused by cold soldering due to oxidized leads.