That is very difficult to answer because a lot depends on how your data is structured, how you applied your filter and of course the details of the conditional formatting.
Therefore I suggest that you try to recreate that in a new file with e.g. 500 rows of data (number from 1 to 500 in column A is enough).
If the issue persists:
Login to https://onedrive.live.com (Use the same Login ID and password as for this forum).
Click Upload in the top and choose your file.
After uploading, right click the file and choose Share.
Click Copy Link in the lower left edge (no need to enter an email).
Copy the link and paste it here.
Andreas.