DNS request not received when mixed case query is used

[ndmalc]

Interactsh version:

web (app.interactsh.com) using oast.fun
interactsh-client (v1.0.7) using oast.fun

Current Behavior:

No DNS request are received from interactsh client when DNS request are performed from specific DNS servers. I identified that said server is performing mixed case dns query. HTTP request are properly received on the other hand.

Expected Behavior:

DNS query are received by the interactsh client.

Steps To Reproduce:

1. Get interactsh token
2. Make one or more letter of base domain (usually TLD/TLD+1) uppercase
3. Do command 'dig @ns1.<base_domain> <uppercase_token>' ex: dig @ns1.oast.fun cf08e2g2Vtc0000T9v70g8osydoyYyyyJ.Oast.fun
4. Never receive DNS request from the client

Anything else:

Talk of mixed case dns query: https://isc.sans.edu/diary/Use+of+Mixed+Case+DNS+Queries/12418
Upper case letter in the random part of the token does not create any issue only the domain part