ABGT
I had a 7mm Rem Magnum that did exactly that - with brand new unprimed Winchester brass.
The first loads were just 'starting" loads to work up from there, I split at the neck just like that every case I fired, yes there was a bad batch of brass that came in & it was taken back by my gunshop & exchanged.
Annealing is not a hard task, I use a 17mm long socket with a coachscrew's thread turned down to fit through the drive & into a battery drill. An old primus torch with a small nozzle for soldering & a bucket of water to tip them into.
I've tried heat sensitive crayons but they melt the same colour as the brass!
So I simply heated the neck & just over the shoulder region of the case to a slight change in colour whilst on very slow speed & dunked in water to avoid any extra annealing towards the head.
Do not heat cases to cherry red - they're buggered if you do that!
I have 9.3x64mm (RWS) & .308 Norma cases that I've had for over 25 years; I don't do a lot of shooting like most of you blokes but I religiously check for any internal cracks, splits etc every time after case cleaning - no losses since annealing!
If the brass is still good & hasn't split then I would anneal, it will extend the normal case life way beyond the normal 10 or so reloads.
regards
93x64mm