If you activate Staking or Lending for a specific coin, the total quantity you have of that coin will be activated for Staking/Lending.
If you set up Recurring buy for this coin, the quantity of coins you receive will also be automatically staked or lent.
For example:
You have 1 BTC in your Vault, which is activated for Lending. You receive weekly rewards on this.
Then you set up Recurring buy for BTC, investing €100 weekly.
The coins you receive weekly for this €100 will then be automatically activated for lending!
Have you stopped Staking or Lending for a particular coin?
Then your Periodic buy for this coin will NOT be automatically activated for Staking or Lending.
If you want this to happen, you need to reactivate Lending or Staking for that specific coin.