Great question, @Nancy Bugajski! I had this issue when we switched to a new ERP system. A bunch of the values were prepended with that question-mark character. After a bit of research, I discovered that this was Apptio's way of showing non-printing characters (NPCs) in the uploaded data. At first, we tried to have them fix the issue in the source system. However, Finance was very...well...they simply refused to even consider it. So, we had to find a solution on our end in Apptio.
Eventually, we settled on using the Edit Existing Column function in the Formulas step of the transform pipeline. The formula that quickly became the most efficient and effective was the ReplaceRegEx() formula. If you know how to form a proper regular expression, then this function works a charm.
For example, we have one formula like this.
Journal Name = ReplaceRegex(Journal Name, "^?(.*)", "$1")
This tells Apptio to replace the value in the Journal Name column with the regex result. The regex formula above isolates all the characters after the first character in a string. The parentheses surround the capture group, which is then referenced by $1 in the next argument. You can have more than one capture group in your regex; just reference the one you want to use in the last argument.
Since your NPC is in the middle of your string, then you could have one capture group before the character and one after the character, then reference both in the last argument of the formula. Something like this (I haven't checked this regex, so you might need to tweak it)...
Column = ReplaceRegex(Column, "^(.*)X(.*)$", "$1$2")
Here, you'll need to replace the X with the specific character you want to remove from the string. I suggest just copying and pasting it into the formula. It tells Apptio to replace the string in the Column column with the concatenation of the first and second capture groups in the regex. Since the NPC is outside the two capture groups, then it will not be included in the concatenation.