On a multiplayer server (tested in single player, did not occur), in version 18w16a (possibly 18w19b, however there is no server jar to test this with) any scoreboard objectives containing minecraft:used <item> after the server is restarted, are deleted. To verify this I did the following:

/scoreboard objectives add Test minecraft.used:minecraft.acacia_bark

and after restarting the server did /scoreboard objectives list, Test was not there, and I also tried setting my score of Test, but was unable to since it was not there. A scoreboard using its old name (in this case, "Test") can be re-created just fine, however.

Related: Any dummy objectives that are being used in a command block after a restart seem to reset the players score of that objective, for example if I have an execute if testing for my score of a dummy objective, restart the server with a score of 1, and then restart the server with that command running, upon re-logging in the score will be set to 0. Best way I could explain this. It seems to be only for certain dummy objectives, but that may depend on how they are used. I have a lot of command blocks running at once, and I know for certain not a single one would change the score.