Why do online stock updates take so long?

[KIB2014]

For a restaurant, quick updates are extremely important. The stock updates seem to be taking a long time, for both in stock and out of stock items. Anyone else having this issue? 

[DinaLRosenberg · Accepted solution]

 I call this the square "gremlin".. sometimes stock updates are instant- sometimes there is a lag. No telling how the gremlin is going to behave.