Clicking any of the Theme buttons more than once causes the page to go blank

[WaveScouting]

On PC, haven't tested on mobile.
Pressing any of the theme buttons more than once causes the page to blank.
Error thrown by console:

SyntaxError: Failed to execute 'add' on 'DOMTokenList': The token provided must not be empty.
at index-DjyZkKgT.js:292:48074
at Zf (index-DjyZkKgT.js:40:24272)
at ia (index-DjyZkKgT.js:40:42382)
at t8 (index-DjyZkKgT.js:40:41205)
at Ii (index-DjyZkKgT.js:40:40254)
at DS (index-DjyZkKgT.js:40:36864)
at vi (index-DjyZkKgT.js:38:3274)
at index-DjyZkKgT.js:40:34246