G8 LED Bulb Dimmable 3W Mini Thin Puck Light Bulbs Equivalent to 20W-25W T4 G8 Bi-Pin Base Halogen Bulb, 120V Warm White 3000K G8 Bulb for Under Counter Kitchen Lighting, Under Cabinet Light (8 Pack)

I just found a 3D printable replacement cover that may be close as well. It does not have the grooved holes which I believe are for ventilation, but that should not be a problem if you use LED lights that don't put out much heat. I think the heat destroys the original plastic ring over time, making it brittle and prone to breaking which leads us here. The 3 little hooks on the inside look similar. No idea if it's the right size or anything though. Anyway, I don't have 3D printer but the local library will print it for free so I'm going to have them do it and I will try and see if it fits. You should look into it as well, see if you can have one printed and try it out. Maybe we'll get lucky and it will work? Here's the link: https://www.thingiverse.com/thing:5568261 These are the bulbs I switched out (I needed soft white and dimmable). They work well and don't flicker.: https://www.amazon.com/dp/B07K9Q7MY1?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2