Bug when selecting every 4 weeks reminder

There is a bug when choosing to set a reminder ever 4 weeks, example -
I get paid from work every 4 Thursdays from work, so I input this months payday April 19, and in the settings I selected a repeated reminder every 3 Thursday (NOTE: this could be simplified by added an "every 28 days" option). The next reminder is in May and on the 17th which is correct, however the next reminder for June is incorrect where it should have set the reminder for the 14th, it has added an extra week and has set the reminder to the 21st (see images below) which is incorrect.

I hope I am not overlooking something here, but I have added the reminder 3 times to be sure with the same result.

Keep up the great work, best OS on the planet!


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