I have notices this on a couple of different occasions. Some shards show that my health-regen is 42 of 41 (Overcharged) when it's only 34 in actual fact.
Then ensues a number of logouts and logins until I get a shard which is calculating it correctly. I only have health regen on 2 heavy Armour items for a total of 16%. And then a set which gives me 18% health regen. No potions, nothing else which can bump it up.
This also counts for the lag, some shards are definitely slower than others. Can ESO please ensure that all the shards have the same code??
"I don't have the time or the crayons to explain it to you"