short_open_tag = On
is not a regular php configuration
if all php tags over the project were opened in short manner than it would be a rule for the project and this rule should be represented in installation instructions: "prease reconfugure your PHP on hosting". Its not always avaliable on different hostings but OK.
but if it is the very only one tag from all over the big project - its a BUG.
All projects should be tested with the most common settings the user can have, higher level of security and minimal options turned ON and very common memory or hardware configuration.
If something should be changed from common server configuration - user should know it from installation instructions but not from digging Your code for couple hours or waiting a week on forum or wasting time for digging troubleshooting.