Samba4 creates files as executable when parent directory has any default POSIX ACL

Question

I have a Samba 4.5.12 file server running on Debian Stretch with a file share configured as follows:

[test]
    path = /srv/test
    read only = no

Inside that share there's a directory: /srv/test/directory. Using Windows client I then create a file test.txt and after creation it has the following permissions:

# file: test.txt
# owner: some_user
# group: some_group
user::rw-
group::r--
other::r--

Now, on the file server I then set a default ACL on /srv/test/directory directory:

setfacl -d -m group:some_other_group:rwx /srv/test/directory
touch /srv/test/directory/test2.txt

test2.txt file has permissions as expected:

# file: test2.txt
# owner: some_user
# group: some_group
user::rw-
group::r-x                      #effective:r--
group:some_other_group:rwx      #effective:rw-
mask::rw-
other::r--

When I then proceed to create another file using Windows client I get this:

# file: test3.txt
# owner: some_user
# group: some_group
user::rw-
group::r--
group:some_other_group:rwx
mask::rwx
other::r--

As you can see the mask is wrong. How can I fix this?

I tried setting create mask = 0666 but that did not help either. The only thing that helps is disabling NT ACL support via nt acl support = no but I don't want to do this.

Full smb.conf is as follows:

[global]
        server role = member server
        security = ADS
        workgroup = *redacted*
        realm = *redacted*
        netbios name = FILES

        kerberos method = secrets and keytab

        acl allow execute always = yes
        map to guest = bad user

        store dos attributes = yes
        map readonly = no
        map archive = no
        map hidden = no
        map system = no

[test]
        path = /srv/test
        read only = no