can't write files to an SMB share from Kate/Kwrite/Kdevelop after latest -current updates

Hi all, I'm facing this strange problem

I'm using Slackware64-current on my PC. I work on a SMB share (shared by a Slackware system) mounted locally

The share is mounted RW, and was working for months. But now (I don't have notice of when exactly started this problem, but for sure in last days) I can't write on text files on the share from Kate/Kwrite/Kdevelop.

I have full write access to the same files on the share with any other tool (libreoffice, vi, nano, calligra..)

I think this may be a bug of integrated KDE text editors, which (I suppose) shares the same engine. All of them wasn't having this problem since few days ago..

I tried to use strace to debug (with kwrite), I report here the part that I think relevant

Code:lstat("/mnt", {st_mode=S_IFDIR|0777, st_size=4096, ...}) = 0
lstat("/mnt/public", {st_mode=S_IFDIR|0777, st_size=0, ...}) = 0
lstat("/mnt/public/ametis", {st_mode=S_IFREG|0777, st_size=955, ...}) = 0
getpid() = 17039
openat(AT_FDCWD, "/mnt/public/ametisV17039.new", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0600) = 19
fcntl(19, F_SETFD, FD_CLOEXEC) = 0
stat("/mnt/public/ametis", {st_mode=S_IFREG|0777, st_size=955, ...}) = 0
fchown(19, 1005, 100) = -1 EPERM (Operation not permitted)
fchown(19, -1, 100) = -1 EPERM (Operation not permitted)
stat("/mnt/public/ametis", {st_mode=S_IFREG|0777, st_size=955, ...}) = 0
access("/mnt/public/ametis", R_OK) = 0
access("/mnt/public/ametis", W_OK) = 0
access("/mnt/public/ametis", X_OK) = 0
chmod("/mnt/public/ametisV17039.new", 0777) = -1 EPERM (Operation not permitted)
openat(AT_FDCWD, "/mnt/public/ametisV17039.new", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0666) = 21
fcntl(21, F_SETFD, FD_CLOEXEC) = 0
lseek(19, 0, SEEK_SET) = 0
close(19) = 0"ametis" is the files I tried to open and save from kwrite

I try to ask for help here because I don't know how to manage this error