> The actual method of conversion involves a complicated curve that isn't continuous

Isn't continuous? Really? That seems surprising to me; tell me more.

it's complicated for appropriate values of complicated.

more specifically it's defined piecewise and the standard then rounds some constants in the definition, which results in a slight discontinuity around the transition from one piece to the other.

https://en.wikipedia.org/wiki/SRGB#Deriving_the_transfer_fun...

A piecewise function is definitely not what I'd call "complicated".

It's an implementation detail. In theory, it should be continuous.