Saw that all white, pink, and purple Boba housings are being phased out due to discoloration (source) AND Gazzew is working on some new switches. I remember discoloration of some Bobas being discussed over in the GMK Bleached thread and it seems like off-gassing is the culprit for Bobas at least:
Edit: it seems like Ringer Keys still has U4T 68g Pearl Top switches in stock when you order at the “1” quantity. You can specify any number that you want, so long as it shows “1” in the switch pack size dropdown.