I'm using Defined PBR which is created by user MADLAD3718. The copper grates currently don't have any PBR materials applied to them. Though I make my own RTX edits and can check if the issue persists with them applied. Changing the transparent pixels to 1% opacity white does mitigate the issue, but introduces a lot of other issues such as making the block refract light similar to glass, and the inventory item doesn't look correct.
Want to add a little note that if you use multiple RTX resource packs like I do, you have to toggle this setting on and off multiple times. I have two RTX packs loaded when I play and toggling on and off once only loads the first set of PBR textures and toggling a second time loads all of them.