Answer:
These are the problems that are not severe enough to prevent processing. They mainly complain about the previous version of your document. In the case of command invalid, the latex gives a warning and henceforth it needs to be fixed.
Explanation:
There are some bugs in which they are not that severe that make the system not process.. but they are still mistakes in which might affect how the program run those parts.. like in JavaScript in the program i use, the minor bugs are like symbolized as yellow triangle and they are normally like signalizing a grammar error in the code and the app still runs but just that part of the code is invalid or reads wrong.. while big errors like codes that dont make sense, those make a red squareish that as soon as you try to run the program the debug console states in all red "Line 50(or whatever line) SyntaxError" or other things
