Basic mystery looking for help/info - class mastery scraps are no longer dropping from my (1) daily master writ, and have hypothesis but need to confirm.

1- Main char recently got 50 scraps, combined them, got Class Mastery grimoire from that combination, used it to learn skill.
2- Then immediately went to Scholarium to buy Class Mastery grimoires for all 19 other alts. Therefore, -ALL- chars on main account knows Class Mastery grimoire.

3- Noticed yesterday after usual craft session + master writ turn in, that no class scrap dropped on my 1st master writ turn in of the day (as it used to do)

S0 - the mystery is whether class mastery scraps no longer drop from any of the prior sources (master writ, random daily dungeon, VMA clear, etc) because:

Possibility A: The game knows that every char on this account knows Class Mastery, so no point dropping anymore scraps.

Conclusion A: Mostly ok, but leaves the odd scenario of how does game know I won't create more chars in future? For me, am already max slots at 20 chars, so no issue. But what if someone had 15 chars? Wouldn't it be nice to collect scraps so you can get freebie grimoire for those future alts?

Possibility B: The game knows that this current char that turned in master writ knows Class Mastery, so no more scraps drop for this char. e.g. game doesn't care if all or none of alts knows it, just whatever char did the activity no longer earns class scraps if that one char already knows it.

Conclusion B: This would be terrible under all scenarios. And if intended, very bad game design. If unintended, then a moderate bug. Yes, it's not earth shattering, because once ONE char knows Class Mastery, all alts can buy at vendor with gold (10k each). But since 50 scraps combine to form 1 class mastery grimoire, it would seem obvious to allow those not in a super rush to continue to collect scraps from normal game activity, and slowly over time use them to scribe free class mastery grimoires for alts.

Request - what I'd like is some player who (i) knows class mastery on that char but (ii) does NOT know it on ALL alts on that account to do a master writ, turn it in, and see what happens.

Either that player will earn a scrap - which means game doesn't care if that specific char knows class mastery, as long as someone on account can still learn it, will still drop scraps. Which is good. Let's you continue to use main char to farm for your alts.
-OR-
No scrap will drop, which means this kinda sucks and punishes players using main char to do most daily activities. If no scrap drops, that would confirm that you'd have to do that scrap activity on a char that doesn't know the grimoire yet.

Please reply if your char fits criteria above and let us know if scrap still dropped or not. Thx.