GCD - yup very strong cinnamon flavor
CLS - getting nothing but a burned taste - my clearomizer is clean with a new coil in it.....I tried it again and now am getting a bit of a custard taste - not sure why the first couple of hits were burned
Frenilla - very mild taste, not much to it yet
Strawnilla - very mild taste, do taste a strawberry but barely
(disclaimer) I hope this doesn't come off as "the liquid guy always blames the hardware, and the hardware guy always blames the liquid."
While the possibility exists that the liquid just isn't for you, I feel like that's a long shot given that you have a nice cross section of the liquid and it's statistically unlike that all 4 will fall flat for any single person.
On the Frenilla and Strawnilla, I will be the first to concede that they will definitely benefit with time and patience - but even at it's present age, "mild" isn't a descriptor I would use to describe either... immature is a better description (to me). I need to revisit your order number (PM me) and I can tell you exactly the GCD and CLS were mixed... but... honestly, the likelihood that it's a steeping issue (I feel) is slim to none.
Are you on stock coils?
Do you know the PG/VG ratio of the liquid you are coming from (or, that works?)... burnt taste is typically a case of "the atomizer isn't getting enough liquid." I would start at the lowest possible voltage setting and gradually work your way up. Give it a couple "primer puffs" to suck some liquid into the chamber before you start. Then gradually increase the voltage until you get "that burnt taste." back it down by .2 volts, give it a couple primer puffs, and you should be fine.
Also - new head? bad head possible? (Aspire heads are notoriously inconsistent since there are a ton of people out there selling what appears to be authentic Aspire products, but they are counterfeit) Is this across multiple tanks?
Also, might not hurt to try the same tanks on a the passthrough to see if your battery isn't putting out wonky voltage, but I feel like that's a long-shot also.