If the sickness has part day ticked but showing as a full day please go to the absence in question, open the absence record, and look at the tick box called use working pattern.
The tick box sits just above the working day's value. Is this ticked?
If yes, then untick and enter the correct working days value. 3.5 days for example. If it's not ticked, this looks to have been entered incorrectly. Enter again the correct working days value, 3.5 days for example, and then save the absence, and the summary on the record will show as 3.5 days.
📌Note: If this is still not correct then you need to contact us.