i ran into your lily pad mod as i was testing compatibilities for my lily pad mod.
nice idea, but lily pads become invisible when i put a torch or candle on them.

my mod list: fabric: 1.20.1, sodium: 0.5.0, betterlily: 1.3.1.

You got indium right?

i didn't.
but i added it just now and it didn't help.
and i updated sodium and indium two versions up, it didn't help.
then, just because i am feeling helpful, i removed all mods that could possibly cause a problem. it didn't help.

any more ideas? i too expected sodium was culling the lilypad, but no...

changing the lily pad model through a resourcepack doesn't help.

your block stays invisible. breaking particles are black and purple.
the only thing in log are two orange lines saying
[10:29:56] [Render thread/WARN]: Failed to get file path of mod betterlily: /
[10:29:56] [Render thread/WARN]: Failed to get file path of mod moonlight: /

Can you replicate on a new instance with no other mods?

same.
new instance in Prism launcher, fabric 1.20.1
minimal list of mods, nothing configured, just copied:
betterlily-1.20-1.3.1-fabric.jar
lib--fabric-api-0.87.0+1.20.1.jar
lib--moonlight-1.20-2.8.6-fabric--needed-for-EC-and-lilies.jar