Sounds like a hotspot. A small offset will have a significant hotspot - requiring a larger baffle between the firebox and smoke chamber.
Even on my big Lang... will run very hot - because the firebox is partially notched into the smoke chamber.
The first foot nearest to the firebox... is my chicken chamber.
Suggest running a biscuit test and verify your temperature range shown in this thread.
Custom Klose Backyard Chef... of Snot, and a 22.5 WSM
Lang 84 Deluxe kitchen, Lang 60 Mobile - The Damsel II, Lang 48 Patio - The Damsel, Bubba Keg Grill - RIP, Double Barrel Smoker and a BSKD