Basic equal and not equal not working?

Two sheets in my very small (2010)workbook grab values from separate workbooks.
(The outputs of 2 separate databases)
My main sheet is simply used to align the separate data and check for errors.

Several columns are compared with a simple conditional formatting =$B1<>$P1 or =$B1=$P1
Works for the most part, but about 1 out of 10 are conditionally formatted in error.
Copy/pasting the values directly into notepad reveals that they are identical
For example,
TSG
TSG
no spaces to consider (since the other sheet draws the data with a TRIM(A1) )

cells being compared are formatted as text or general - no difference.

if this was the entire column I would stick with it, but just randomly not working?
strikes me as a bug.
Any ideas? This is a main reason why I built this comparative workbook.

ug. Thanks for the suggestion.
Just did the LEN() for two columns and got matching numbers
Only reinforced with SUBSTITUTE()

OK, I deleted all but the offending columns - (to make a sample)
(Obviously had to rewrite the conditional formatting)
Problem vanishes.
Ug
I will try to find the point of error and get back to you.

Thanks for the help. Problem found.
My conditional formatting "Applies to" area was done by row =$B:$B and my equation did not use B1, but rather B4.
O_o

"Is the computer plugged in?"