Yes, this bug was reproduced on my machine as well.

>The code should read as follows (I hadn't changed the bbb var TO lchtml after testing - sorry, rushing ... :)). Also the verion taken into the clipboard from UT gives 1801 as a result.
>
>

>*parsetag.prg
>LOCAL lcTag, lcHtml
>lcTag = [~SELECT NAME='cboempguid' ID='cboempguid' SIZE='1' ] + ;
>        [STYLE='BACKGROUND:~%=IIF(poError.EmpGuid, 'red', ] + ;
>        ['#FFFFFF')%~;FONT:normal normal 9pt Arial;HEIGHT:24;] + ;
>        [LEFT:310;POSITION:ABSOLUTE;TOP:0;WIDTH:194' ] + ;
>        [VALUE='~%=potravail.empguid%~' ] + ;
>        [~%=IIF(PLDISABLEEMPLOYES,'DISABLED','')%~~]
>lcHtml = REPLICATE('0', 1800) + lctag + REPLICATE('0', 11000)
>? ATC(lctag, lcHtml)  && result is 0
>? ATC(UPPER(lctag), UPPER(lcHtml))  && result is 0
>? AT(lctag, lcHtml)  && result is 1801
>
>? ATC(LEFT(lctag, 255), lcHtml)  && result is 1801
>