You'll have to parse the data for those columns.
Instructions are available here.
Basically you create a microflow that has a String as the parameter, then some logic to handle the string.
The output of the microflow is the parsed string.
Once the microflow is created you can select that microflow to parse the column data in the import template settings.
Hope this helps.
Please review this logic and let me know if you can help me out to resolve this issue