Notice the direction of that backslash. What they were trying to do was ๐^๐ฆ^ on the power of ๐ฆ, but I guess this formatting code doesn't apply to titles.
EDIT: ...or lemmy comments. Testing: (๐^๐ฆ^)^๐ฆ^ - nevermind. So they tried to escape the exponential symbol with a backspace, but there was no need for it in lemmy, since it's coded differently here.