Adansonia germination issues

[Jangaudi]

hmmm, ok, here's the settings :
I recently sowed Adansonia digitata, just regular sowing, in the pot...couple weeks later I had one seedling. Then I waited patiently for another 2 weeks...nothing. I took out the remaining seeds and gave them a thorough sand paper scrub. Most of the seeds germinated within 3 days....pretty neat. So that's that.

Weeks later I got some Adansonia grandidieri seeds to sow, so I thought : "Let me just give them a good scrub before planting, and they might pop up much faster....." So what happened is that half of the seeds started getting mushy / rotten after a week or two, not much else happened..... really bad !!

So, now I recall an instance where I sowed Bowiea volubilis, and gave them a good scrub too (as I read that online somewhere) and pretty much the same thing happened....soft mushy seeds, no germination.

Now I'm wondering if there's a possibility, that giving them a sand paper scrub might make the seeds take up water too fast, before the germ wakes up and thus sends the whole thing rotting ?
Any ideas ?
There's a chance the seeds were just bad, but the similarity does ring a bell.