Edit in Grid Mode stops working after updating a people column

Hi there, hoping someone can help please. I am importing a list from excel which has 152 rows, 20 columns. 

I have 2 columns which are people, so I import them as 'Single line of Text'. Once imported I create a new column (people) and go to 'edit in grid view', then i start to add the people in correctly and it picks them up from our system. I exit grid view and it all saves fine. I then go to edit in grid view again and it does nothing, all the records disappear and it just says 1-100 and the page is blank. I refresh, all the rows reappear but not in edit grid view. this functionality just seems to stop working after i have edited one column. I just cant seem to understand what the problem is!  

Does anyone know what could be causing this? I am just a user with owner rights, I don't have any admin rights to the site. 

thank you.