My phone abruptly power off at a random battery percentage

I recently got my phone one plus 6t battery replaced it ran smooth for 3 months for last week i have experienced and issue when i charge mu phone and use it till it reaches 40 percent or below at a random percentage my phone abruptly shuts down and after i try to power it on it show in multiple languages that battery is too low charge to power on and after i plug in it starts charging from 0 percent and when it reaches enough battery it turn it on and by seeing the usage detail in setting it shows graph from 100 to 50 discharge percent but after 50 the line ends and no data is shown after that why? And also i have hard reset my phone as well as i have factory reset it but no success. After it turns of abruptly it says in red text and many lines each for the same sentence but different languages that phone battery too low charge before powering on. What could be the issue please help