According to HexRays IDA support, this means an error. In IDA help (press
F1), under the
Problems List header you have the list of possible problems encountered during analysis. In your case it seems to be
BADSTACK, which means:
The value of the stack pointer at the end of the function is different from its value at the start of the function. [...] The most probable cause is that stack tracing has failed.
You will see each line causing this problem in the
List of problems window.
The description how to fix this problem is included in the IDA help as well, below the problem description.