rs.c bug about qrcode recognition rate being low

[FengMu1995]

when I run the code with qrcode, it slightly move, it results in qrcode no parsed information.But sometimes, I move really obviously, it can be recognized. So,
I found out, that rs_correct (in rs.c) returns a value of -1 for the qr code, what in turn causes the decoding failure. The reason for the negative return code is that rs_modified_berlekamp_massey returns a value of 15 for the qr code but rs_find_roots only finds one single location.
I wondered why? And How to solve it?