I have worked for Stihl dealers for many years, which is why I responded. No, it won't hurt anything, Stihl looks for abuse like running with no guard when there is a clutch failure. If you should ever have any problem, be smart and wind back in the smaller string and don't bring up the topic,
but on a homeowner little trimmer like that, you won't have any problem. If you do, contact me here and I will mail you a new clutch for free, as
I sell those parts online, and the clutch and drum is a very slow moving part.