Please provide code when possible.
There could have been a change, in p5.js or in chrome, but the most common reason to believe that your antialiasing is suddenly broken is to forget to add background() to a sketch canvas or graphics buffer. Not clearing the screen causes antialiased layers to build up over multiple frames, making smooth edges look crunchy.
Not saying this is your problem – just that it is a very common reason for people to search the forum for “smoothing not working”.