Unfortunately you cannot exclude a single suggestion that VA has picked up from the surrounding code. If this is a suggestion then you would need to turn off all suggestions.
There are a couple of things that might be happening here. This could be due to:
VA Options -> Advanced -> Correction -> Repair case
so can you try turning this off and see if it makes any difference?
If turning off one, or both of the options:
VA Options -> Advanced -> Suggestions -> Include suggestions in listboxes VA Options -> Advanced -> Suggestions -> Include bits of code from surrounding lines
helps, then we know this is a suggestion. Do you mainly use "i"? If you use this much more often than you use "I" you could try adding a VA Snippet with the shortcut "i" to insert the code "i", but this might cause problems on the few occasions you do want to enter "I".