I remember back at one point (not sure how long ago) people were saying that if they had too many items in their inventory that it would get glitched or "break". A friend of mine has been absent for all of Vesnali and I have been giving her a lot of flowers. Now I am worried that she will have way too many coins in her inventory. Is that going to cause her any problems? I am trying to do something nice for a friend, so I would feel terrible if it ended up causing her any account issues.

there have been problems lately. The safest thing your friend can do is go to Esther's shop and turn in the coins without trying to add them to her vault or shop/gallery. Generally, the glitch happens when the site is trying to move a large stack of items to somewhere and the site times out and you get one of the 502/503/504 errors.

Your friend should write down how many coins are in inventory, how many are currently in Esther's and then make sure they all get added. If they don't, file a ticket with the information and the coins should be returned.

She has not been on yet that I know of. I will leave her a comment and hope she sees it before she goes to her inventory. Thank you for your help :)

No problem! I lost a bunch of Vesnali coins, submitted a ticket and got them all back :).