Visitor log showing visitors, but no actions

I’m having trouble understanding this one. For two days in the month of march, the visitor log shows no action as seen in the picture. All days before and after those two days show the visitor log correctly.

I thought that maybe there was a problem with the type of field used in the log_link_visit_action as suggested in the following post :, but it does not seem to be the problem as we are still under the int limit.

We are currently using the 2.16.2 version in production.