This is bug in 17.3 in multi-line string and comments that several of us have hit. A fix has been promised for 17.3.1 "Soon"
Most of my colleagues has reverted to 17.2 or 4.2 until this is fixed.
thx for your answer. I was waiting for that version, because of another bug. I had to revert to 4.1.3. Hope the fix will be provided soon.