If she's anything like me (!) I need to go about every two hours just before I 'come on' - maybe you could make an effort to take her out a bit later and let her out a bit earlier - or put a bit of paper by the door if that's not practicable ....
They usually hate doing their jobs inside once they are toilet trained, and I have found with my un-neutered bitch that the only time she gets caught short is just before she is in season ...
Becuase I now have 2 (Bramble is now 2 yrs old) she thinks she can get away with blaming it on him, but unfortunately for her, we can tell their poos apart (don't ask me to describe, but we just can) so ....
However, if we walk in on a 'little surprise' of whatever consistency, we don't fret and fuss - we just clean it up and say Oh Dear, Never Mind ... Gosh, What Ever Happened Here
Unless there is something else underlying, I would suggest that she either didn't do her toilet in the evening or the morning; was left for too long after that; just got caught out; or has found a nice place to toilet and isn't having enough reinforcement about being 'good' outside. Displeasure can go quite a long way, but not nearly as far as praise, so do start again from the beginning and tell her how good she is for being 'quick' or 'tiddly' or 'jobby' or whatever key-words you use ...