When I finally Googled it the other day it said that's the default. Get an intervalometer. Lol. It will change..Just not to "seconds" just fractions of seconds.
I bought the SL3 specifically to do Time Lapse. Only to find out that it's basically TL for DAYTIME. The Shutter Speed is only set at a default of 1/30 sec, etc.. to enable it to combine shots into a video. I do Astrophotography. Takes "seconds"...