I cannot reproduce this, sorry. I even copy/pasted the formula you used and got 72 damage (using Harold, Marsha, and Lucius from a dummy project). Could it be some sort of elemental property of the attack? A typo? What happens when the damage formula is simply "c.mat"?
Viewing post in Bug?: MAT based tech issue
Hi, even with just c.mat, I got the same issue, 0 damage, but no issues once I use a.mat. However, I also cannot replicate this problem, so I really have no idea where is the issue, especially since my other techs work just fine. I did wonder if the component actor/skill could be the issue in my notetag, because if I changed it to c.atk, it still does not work, plus the cost is showing up correctly.
I basically tried the following, and nothing still tells me why it does not work:
1. Remove all notetags which are not related to this plugins.
2. Tried a different stat
3. Tried different skill type
4. Tried disabling other plugins
I will keep seeing what else I can try to see if I stumble into the solution, but I have a feeling it is just something on my end, or something interfering with the script of this specific skills, since other techs work perfectly fine.
EDIT: After installing the latest plugin, the issue still happens, but I believe I know the reason, and it is likely because of SRD plugins, and this time it is SRD_SummonCore. I tried activating the Dual Tech with actors that do not have skills using this plugins, and it works (mostly) fine, even if the dual tech in question involves actors with skills using the Summon Core plugin. If I tried activating the skill using the actor who has a skill that summons another actor, however, the formula stops working.
I think SRD plugins might change something inherent in the system or just conflict with your plugin somehow as long as it is installed, because similar to the other test you did, I managed to repro the error even with the plugin turned off. Removing it does not work either, as it seems that the "damage" is already done once the plugin is added. However, I am no programming expert, unfortunately.
The key thing I found here seems to be who is activating the skills is important as to whether the c.xxx, d.xxx, etc pulls the actor stats.
It's possible that the plugin might override Game_Action.prototype.evalDamageFormula, which means "c", "d", etc. would never be defined. For some reason I find incredibly irritating (it doesn't let a game dev find errors in their formulae) any damage algorithm errors simply cause the damage to resolve to "0" instead of throwing an error, so it's hard to say without looking at the plugin in question. And I can't reach SRD's site right now.
I agree, it's incredibly irritating that instead of showing an error, it just resolves to 0. Unfortunately, I have not much knowledge on RPG Maker MV and the scripts behind them, but I tried opening the plugin in notepad, and I could not find any "damage" related script.
Could it be an Actor ID issue instead? I did find tons of reference to actors in SRD's script.