Totally normal response most people do to some degree or another (especially parents of small children, but even young single people tend to prefer to "come home from work" ; meaning take a bit of time to destress, shower/change clothes, relax for a spell, & gentle the transition... It just becomes a huge issue for many if not most parents because leave one job, and come home to another job! And if you've got a SAHP, they've also been working all day wih the kids & want their lunch break / time to switch gears / relax & refresh also...so both peeps really need a break & those need to be coordinated).
PLUS
PTSD doing its thing and kicking everything up a notch! Turning tired into exhaustion, irritation into rage, the sound of a fork being set down in another room into a cymbal being clanged next to your head.
I've found the exact same tricks parents use to not go batshit crazy and hate coming home, no matter how much they love their kids, works really really well. AKA DONT come straight home. When I'm doing well & PTSD isn't a problem? That means stopping off at a cafe 2 minutes from home (or from daycare) to wash my face, change my clothes, & read a book while having a snack... For about 15-20 minutes. When I'm doing badly? I generally need a whole hour or hour and a half; and I really do much better to stop by the gym, work out, take a full shower, change my clothes, eat something, and relax. THEN :D and Yaaaaaaay! Mom's here! ((Or sans kids, YES! I'm actually freaking human again!)).
So, for me, the PTSD really makes it a matter of degrees; how badly I need the time to decompress, and how much time & effort it takes.
15-20 min vs 60-90 min
Wash my face vs Shower
Whatever is fun vs Exercise + whatever is fun
Snack vs Meal
Etc.