An often missed "feature" by most customers (from the NAV 2018 help files) - If the lot accumulation period is less than the dampener period, then the dampener period is dynamically set to equal the lot accumulation period. This is not mentioned in the Microsoft Docs site for he planning functionality at the end of this document...

This is troublesome for pretty much all our customers as they do not expect or want an interaction between the dampener and the accumulation period. If they set the dampener period to 1W (1 week), they really expect that if a purchase order or production order are coming in early inside the 1 week dampener (prior to the demand) they do not want a planning message. It is pretty common to have 1D to 1W accumulation periods but have dampeners set to 1W or more (have seen up to 4W).

Please remove the interaction between the dampener and the accumulation period and respect the dampener regardless of what the accumulation period is set to.

Definition or the dampener from docs.microsot.com - note no mention of the accumulation period:
This field is used to avoid minor rescheduling of existing supply out in time. Changes from the supply date until one dampener period from the supply date will not generate any action messages.
The dampener period specifies a period of time during which you do not want the planning system to propose to reschedule existing supply orders forward. This limits the number of insignificant rescheduling of existing supply to a later date if the rescheduled date is within the dampener period.
As a result, a positive delta between the suggested new supply date and the original supply date will always be larger than the dampener period.