Zebra - problem when printing with linkos - printing

Question

I'm developing a Windows application in WPF, which uses the "link-os" SKD to print a large amount of tickets over a USB connection with a Zebra GC420t. The problem is that during printing, the printer apparently loses the detection of the black mark and begins to print the content in a wrong position relative to the top of the ticket.
Important points:
My software build a ZPL string in runtime and sends it to the printer;
I'm using the "GC420t" driver (non EPL);
Before starting the print job, I send to the printer some print settings:
"~SD15~TA000~JSN^XA^SZ2^PW639^LL799^PON^PR2,2^PMN^MNM^LS0^MTT^MMT,N^MPE^XZ^XA^JUS^XZ"
At the beginning, the printer is correctly calibrated. Sometimes, when the problem reported in this post happens, the printer becomes uncalibrated.
Below, a ZPL sample code, and the link to a video that demonstrates exactly the moment the error happens. Every help is welcome.
Video: Zebra GC420t error while printing
Zpl String:
~DYE:LOGO1,P,P,34149,,89504E470D0A1A0A0000000D49484452...(Intentionally truncated)
^XA^LS0^LT0^XZ
The statement below is repeated for each label:
^XA
^FO70,0^IME:LOGO1.PNG^FS
^FO57,230^GB533,0,2^FS
^FT0,261^A0N,31,31^FB620,1,0,C^FDEVENTO TESTE^FS
^FO57,272^GB533,0,2^FS
^FT0,294^ACN,18,10^FB620,1,0,C^FD^FS
^FT0,316^ACN,18,10^FB620,1,0,C^FD01/09/2019^FS
^FT0,379^AAN,18,10^FB620,1,0,C^FD^FS
^FT0,431^AAN,27,15^FB620,1,0,C^FDR$ 10.00^FS
^FT0,529^AAN,18,10^FB620,1,0,C^FD^FS
^FT0,510^AAN,18,10^FB620,1,0,C^FD^FS
^FT0,492^AAN,18,10^FB620,1,0,C^FDInformau00e7u00f5es sobre o seu evento!^FS
^FT564,475^ABB,11,7^FH^FD008403615029^FS
^FT0,356^ABN,25,14^FB620,1,0,C^FDREFRIGERANTE^FS
^FT67,569^ABN,11,7^FH^FDPDV: TICKET SIMPLES ESC. 29/12/2018 00:50^FS
^FO57,582^GB533,0,2^FS
^FT0,649^ABN,22,12^FB655,1,0,C^FDREFRIGERANTE^FS
^BY3,3,61^FT172,717^BCN,,Y,N^FD>;008403615029^FS
^FT76,472^BQN,2,4^FH^FDLA,008403615029^FS
^XZ
The above statement is repeated for each label.
Thank you all!

Answer 1

Apparently the problem was solved when I set a more precise value for the label size.
I was setting the height of the label to 100mm, when in fact it measures 107mm.
After I made the adjustment, the problem did not happen again.
[EDIT]
Although the procedure described above has considerably reduced the occurrence of errors, even at a lower frequency, it persists. In contact with Zebra's support, we discovered another possible cause: the texts and logos on the back of the ticket are confusing the sensors of the printer (black mark). We're working on the redesign of the label. I will update this thread again soon.