When a preset.zip is imported, values from its preset.xml's <settings></settings> section will be written into the DB table mdl_data. One of these imported settings is the ID number of the field that should act as default sort key. Let's call this ID "PRESETSORTID". It is specified as
<defaultsort>PRESETSORTID</defaultsort>.

The smallest value of the id field of the appropriate mdl_data_fields SQL table is the ID number of the first field, let's call it FIRSTID. If you create a new database activity using a preset and completely delete that activity and re-create it, FIRSTID changes (increases).

The defaultsort field of the appropriate mdl_data SQL table should be filled with
DEFAULTSORTID = FIRSTID + PRESETSORTID -1, however it just gets filled with
DEFAULTSORTID = PRESETSORTID.

This prevents us setting the default sort field using a preset.zip. This is bad because there is currently no other way than using a preset. We only can set the default sort direction (<defaultsortdir>0=ascending or 1=descending</defaultsortdir>), but the default sort field currently is always the Date entered. This does not make sense in many cases.