display occasionally turns white during use

Most likely the display has failed.

A common issue with people cleaning the spray the display panel with a cleaner and then wipe it off. Sadly, the clean can drip to the bottom and under the bezel to some circuity we call a T-CON board which does the hard part of painting the image on to the LCD screen from the signals it receives from the main logic board via the iDP/eDP display cable (looks the same from the LVDS but its different). This wetness corrodes the board and can also damage the cable.

To validate I would connect an external display to see if the issue is visible on it at the same time.

Here’s the needed parts info: Late 2013/Mid 2014 15” MacBook Pro retina Display Assembly, Apple P/N 661-8310 and here’s the guide to put it in MacBook Pro 15" Retina Display Late 2013 Display Assembly Replacement. Sadly they are hard to come by as many people are holding onto their systems and the display maker no longer makes the panel.

@johnnyluca - Pop off the bottom cover, disconnect the battery and charger and carefully disconnect the display cable to inspect it and the connector

Did you see any corrosion? Is the cable connector damaged?

@johnnyluca - Well I think your issue is the battery!! Your battery has over 1,000 cycles and is also very old as its the original battery this system had in it when you bought it.

I'm on my fifth battery in my 2012 15" MacBook Pro, and my two 2015 systems are each on their fourth and they likely need a new battery each as they've been idle for awhile.

Here's a bit my on battery cycles Determine battery cycle count for Mac notebooks Here's the needed part MacBook Pro 15" Retina (Late 2013-Mid 2014) Battery and here's the guide

Substituição da bateria do MacBook Pro 15" com tela Retina do final de 2013