Save Files are being filled with identical lines

I started a game during the Century of Blood bookmark with Aurion Valzyren and around 80 years after the start of this campaign the save files reach around 250 MB due to a line reading "alt_start_disabled_wildling_culture=7898.1.1" being written millions of times (in the last save it was written 4 million times). I saw a report on a similar problem with the "defunct" line filling up the save files and tried the respective solution (something regarding Roberts Rebellion's events) but it didn't work and, since the saving is taking too long, I came here for help.

I do use a few submods: Dueling Duelist, Knights of the Sword Tower, Merchant Marriage, More Bloodlines, Special Buildings Submod, and New Immersive events.

The problem appears in the following section of the save file:

culture=
{
  wildling=
  {
    flags=
    {
      alt_start_disabled_wildling_culture=7898.1.1
      alt_start_disabled_wildling_culture=7898.1.1
      ...

I appreciate all the help
PS: I apologize for my English since it's not my first language