Formulas in excel sheet stopped updating and conditional formatting does not refresh in a timely fashion

Hello,

I am using a shared online excel spreadsheet in a box folder. On this spreadsheet, there is a column referred to as "Time Stamp" which is supposed to automatically refresh when a value is placed in an adjacent column. 

For several weeks after we transitioned this sheet into Box from Share point, this formula worked. However, now with the sheet in excess of 700 lines, it does not calculate anymore. 

The formula is =IF(B1<>"",IF(C1<>"",C1,NOW()),"")

It is a circular calculation, however we checked the box for "Iterative Calculation", so it worked just fine.

The calculation for this sheet is set to "Automatic". 

All cells on the worksheet have the format "General" except for cells with the date, which have the "Time" format. 

For conditional formatting, if a cell in a specific column is changed to "Completed", the entire row should highlight in green. Again, this used to work just fine, and now it has stopped working. The cell is changed to "Completed" and the color does not change immediately. Sometimes it takes a half an hour, sometimes it takes until the next day for the color to correctly change for the entire row. 

Considering all of these functions used to work properly with the document in Box, I am at a loss as to why they seem to have slowed down (like the conditional formatting) or stopped altogether (Like the time stamp). 

While I would normally assume this has something to do with the size of the document, it is only 700 lines and takes up 325 KB with no external connections, Macros, or VBA. 

I am curious if there have been any other reports of excel online operating slowly or incorrectly when used through Box, and anything that can be done to correct the sheet so it functions normally again.