If you own Palico Paintballs (Blue-violet Paintballs), then fulfilling the following conditions will let your Palico automatically use Palico Paintballs to mark monsters:
"Adventure Sync" is enabled.
Walk a certain distance.
Please see details of Adventure Sync settings in this article.
Please note the following:
The strength of the monster that gets marked is decided at random.
Any unused Palico Paintballs will not carry over to the following day.
If GPS usage is restricted on your device or communication line, such as power-saving mode or bandwidth limitation, your Palico may not be able to mark even if "Adventure sync" is turned on.
(11/6 updated at the forum Known Issues article)While hunting a Large monster on the field, Palico may mark that monster, and as a result, the same monster on the Paintball List disappears upon successful hunt. Currently, this is a phenomenon that can occur based on the design, but we are actively exploring potential improvements.