Namecheap doesn't support TXT record in subdomain

[hunhun010164]

Hi, I used your script and want to issue a cert for my subdomain(e.g. sub.mydomain.com) on namecheap. So I configured everything and use command:
acme.sh --issue --dns dns_namecheap -d sub.mydomain.com
And response is:
[Thu Aug 17 11:52:20 AEST 2023] Using CA: https://acme-v02.api.letsencrypt.org/directory
[Thu Aug 17 11:52:20 AEST 2023] Single domain='sub.mydomain.com'
[Thu Aug 17 11:52:20 AEST 2023] Getting domain auth token for each domain
[Thu Aug 17 11:52:26 AEST 2023] Getting webroot for domain='sub.mydomain.com'
[Thu Aug 17 11:52:26 AEST 2023] Adding txt value: ************************************** for domain: _acme-challenge.sub.mydomain.com
[Thu Aug 17 11:52:39 AEST 2023] The txt record is added: Success.
[Thu Aug 17 11:52:39 AEST 2023] Let's check each DNS record now. Sleep 20 seconds first.
[Thu Aug 17 11:53:00 AEST 2023] You can use '--dnssleep' to disable public dns checks.
[Thu Aug 17 11:53:00 AEST 2023] See: https://github.com/acmesh-official/acme.sh/wiki/dnscheck
[Thu Aug 17 11:53:00 AEST 2023] Checking sub.mydomain.com for _acme-challenge.sub.mydomain.com
[Thu Aug 17 11:53:02 AEST 2023] Not valid yet, let's wait 10 seconds and check next one.
[Thu Aug 17 11:53:14 AEST 2023] Let's wait 10 seconds and check again.

I can see a correct TXT record added under mydomain.com with name "_acme-challenge.sub".
But it should be added under sub.mydomain.com with name "_acme-challenge" so that TXT can be verified. Could you please help me with this issue? Thanks a lot.