LUN reached a thin provisioning soft threshold

[silviub]

Hello,

I am using TrueNAS 13.0-U3.1 (planning to upgrade) but I've hit an issue since this morning.
The setup: 3 Proxmox hosts with the TrueNAS acting as an ISCSI storage. Pretty simple and straightforward from my point of view. Since this morning, the Proxmox hosts keep showing

Code:

[Tue Sep  5 12:56:45 2023] sd 6:0:0:1: Warning! Received an indication that the LUN reached a thin provisioning soft threshold.

I have read about VAAI (https://www.ixsystems.com/documentation/truenas/11.1/vaai.html) but the thing is that I'm nowhere near the thresholds:

Code:

Name                Type     Status           Total            Used       Available        %
NAS                  lvm     active      4294959104      1952448512      2342510592   45.46%
NAS_iSCSI_10       iscsi     active               0               0               0    0.00%
local                dir     active       234416128         7364736       227051392    3.14%
local-zfs        zfspool     active       228303992         1252540       227051452    0.55%

This means that there's over 50% free space on the NAS.
The thresholds are set as follows in FreeNAS:
Pool threshold:
Quota warning alert at 90% for the volume we're talking about
ISCSI Extends:
Available space threshold: 90%

Why am I getting the warnings? What's going on?

Any help is greatly appreciated, as I've searched the web for hours now :(

Thank you