No, stop codons are an essential part of of the mRNA. Most likely to be mis-priming of your oligo-dT primer or you have a run of As in your sequence.
If its a run of As, then you'll struggle to get to the end of your mRNA. In which case, you could try ligating a DNA adapter to the 3' end of your RNA molecules using T4 RNA ligase and using a primer against that sequence for RT.