Luckperms 4.4.5
SpongeForge 1.12.2-2768-7.1.6-RC3652
GriefPrevention 1.12.2-4.3.0.662

I currently having issues with the meta set command using YAML setup.
When running the /lp group default meta set griefprevention.initial-claim-blocks 0
I get the following expected entry into the permission file:

meta:
- griefprevention.initial-claim-blocks:
    value: '0'

But when I do /lp group default meta set griefprevention.blocks-accrued-per-hour 0
It changes the above option to:

permissions:
- meta.griefprevention\.initial\-claim\-blocks.0:
    value: false

and enters the following in its place:

meta:
- griefprevention.blocks-accrued-per-hour:
    value: '0'

Am I doing something wrong here or is this an issue with luckperms/griefprevention?
The permissions for both don't seem to be working regardless.

Use the meta add option because meta set replaces all existing entries with the provided one.

I can't tell if that works that way, and have no experience with griefprevention and if you set stuff through the meta-option, but it's worth a try.

There doesn't appear to be a meta add, only in reference to meta addprefix?

Thanks for reporting, this is fixed in the latest version.