I'm on A21 b323 and I can also confirm the problem that @MrMikeTacko and @momoe above have.
Basically you can currently only accept and complete the disassembly quests one time and they don't become "repeatable", even though I checked in the .xml files that they should be "<quest id="disassembleStoneArrowx50" repeatable="true">", assuming they haven't changed something in the newer builds. After accepting and completing the quest for specific ammoType and quantity for the first time, the "read" option stays greyed out if the same quest starting item is attempted to be used, hence not being able to repeat them.
EDIT:
Found the problem in the quests.xml file, the "repeatable" flag is formatted wrongly for all the quests.
Here's an example of the fix for the 762x50 quest.
Original (doesn't work):
<quest id="disassemble762x50" repeatable="true"> <property name="group_name_key" value="Disassemble 7.62mm x 50" />
Fixed (works as intended, aka allows repeating the quest):
<quest id="disassemble762x50"> <property name="repeatable" value="true"/> <property name="group_name_key" value="Disassemble 7.62mm x 50" />
EDIT2:
Here's a google drive link for the fixed "quests.xml" file for the zAmmo Disassembly, so drop that into the mod's folder and replace the old one and you should then be able to repeat the disassembly quests as intended. https://drive.google.com/file/d/1gFd2DNk9GnQINQRIKjm8kpNGYA8Q0bLG/view?usp=sharing . OP, when you update the mod files, I'd appreciate if you can add a small line of credit for this fix.