Scholars will sometimes use Adlo -> Physick when Emergency Tactics is on cooldown if they're desperate to stabilize a pull, they need to conserve MP, and there's still a chunk of Adlo's shield left.
It's 400 MP for a bigger raw heal than Adlo (at 1,000 MP). It's sometimes more efficient to use Physick in these scenarios.
It's mostly in leveling dungeons that this happens. It is absolutely possible to go through Recitation and 6 Aetherflow on the first pull of a dungeon (before Aetherpact is available), and for the tank to still be dying.
It shouldn't be a thing, but they exist.
There were a lot of GNBs at launch who would Camouflage into Superbolide, and also get slammed by the line AoEs in that one pull in Holminster before the second boss.
Combine this with bad DPS that make pulls take forever, and it becomes pure suffering, where you have to MacGyver the party out of some seriously messed up situations.
It's much less of a thing now, and in a lot of cases, Adlo -> Adlo still works because the shield breaks quickly.
I don't think, just by the way you're talking, that you're bad at all.
There isn't a lot of room for error on SCH from 61-74, and not all SCHs are confident enough to use Dissipation (for 3 more Aetherflow).
If the SCH didn't use Dissipation, or they used Aetherflow on Lustrate when Excog was available, that'd be the problem. It'd be a big problem. It's also a very common mistake.