Disable allow-discards on encrypted partition

I have the following partition table:

NAME            
nvme0n1         
├─nvme0n1p1           part  /boot
└─nvme0n1p2           part
  └─crypt             crypt
    ├─crypt-swap      lvm   [SWAP]
    ├─crypt-root      lvm   /
    └─crypt-home      lvm   /home

As the drive is an SSD, I would like to perform [TRIM](https://en.wikipedia.org/wiki/Trim_(computing)) command in order to increase performance/lifetime of the disk itself. In particular, I would like to enable periodic TRIM. Because the second partition (i.e., nvme0n1p2) is encrypted, TRIM will be inhibited because of security implications (https://wiki.archlinux.org/title/Dm-crypt/Specialties#Discard/TRIM_support_for_solid_state_drives_(SSD)) . However, it is possible to enable TRIM on encrypted partition by configuring encrypt on the opening. As I my partition is opened at kernel boot, I've modified kernel parameters (i.e., allow-discards):

cryptdevice=/dev/sdaX:root:allow-discards

(*Note that the partition naming and volume name are not relevant in the above snippet.*). By doing that, I was indeed successfully able to run TRIM command on the disk:

# cryptsetup luksDump /dev/nvme0n1p2 | grep Flags
Flags:   allow-discards

And:

# fstrim ...
/home: [..] trimmed on ...
/: [..] trimmed on

So far, so good. --- The problem arose when I tried to restore to the original state. I have removed the kernel parameter allow-discards, but Flags on partition still shows allow-discards and fstrim command successfully complete its job. * How is that possible? * How to restore denying of discards on the encrypted partition?