mutate from rowwise

I'm trying to mutate from rawwise with dplyr, but it doesn't work.

·Executing the code below will result in an error.

df%>%rowwise()%>%mute(row_max=max(starts_with("X"))))
Error: Notidyselect variables were registered

·Therefore, avoid it

col%>%rowwise()%>%mute(row_max=max(X1:X17))

Then, the largest value does not get stuck.
It contains values like 1.90e-3 and 7.54e-3, so is it not accurate?
(1.90e-3 and 7.54e-3 are on the same line, but 1.90e-3 seems to be selected as max.
1.90e-3<7.54e-3 says True.)

If you are familiar with this, please take care of me.