When I click the free daily coins button I can see the coins go into my account and then immediately disappear. I only have a screenshot for after this happened, but I started today with 31,935 coins. When I clicked for my +75 free, it initially showed the graphic ticking up to 32,010 as expected, but this then immediately reset to 31,935 again. Attached is a screenshot from after the fact.

To recreate this, simply access the shop and click on the "claim daily coins" and keep a close eye on your coin count in the top right.

Refreshing the page and waiting has not yet shown the correct amount.