Stockhistory function producing duplicate values

Hi,

I've been using Stockhistory for some time in excel to get stock data to produce a distribution of returns. For the whole time it has worked perfectly, however in the last few days I've had issues with it. The issue is that it is producing duplicate values e.g. it returns 20/12/2020 OHLC date more than once, and it does this for hundreds of dates. This is obviously incorrect and I have tried everything to fix this. Has anyone else had this issue, and have they managed to fix it. Thank you in advance.