Don’t see ‘charge battery’ screen once phone shuts down at 1%

Replaced battery a while back now, realised after it shuts down automatically once it gets to 1-2% charge, usually when i go to turn it back on without chargin, It shows a ‘plug charge cable in’ screen when you try and turn the phone back on, where as now it tries to boot again with the white apple logo screen.. gets about 10 seconds in showing the white screen on, and turns off again.. then if i try to turn it on again it goes into a boot loop with the white screen.. until i just get a flicker of white every few seconds.. then once i plug it in to a charger, it will white screen, turn off, then white screen and finally boot..

isn’t a major issue at all, just wanted to know what is going on, have tried a sleep button and home button reset (holding for 10 seconds until apple logo) as well as charging till 100% switched off, then home sleep reset again and running it down to 1%.. but still the same..

thanks for any help