Can I study while on post completion Optional Practical Training?

Current guidance from USCIS  reads that "students on Optional Practical Training (OPT) that transferring to another school or beginning study at another educational level (for example, beginning a master’s program after completing a bachelor’s degree) automatically terminates their OPT as well as their corresponding employment authorization document (EAD)" It goes on to say that "Recreational and avocational classes are permissible."  

When does OPT end if I transfer my SEVIS record to another School?

US Immigrations and Customs Enforcement has a Transfer FAQ which indicates that 

"The student's authorization for OPT ends on the transfer release date. Authorization for OPT is not transferable. If the student wants to complete OPT, the transfer-out school must set the release date for a date after the OPT ends. Students can request to transfer up until the end of the 60-day period following post-completion OPT, as long as the transfer release date will occur within five months or at the start of the next available session, whichever is sooner."

When does my OPT end if I request a change of level at Temple University?

"When does OPT end for someone who is changing education levels: When the COL I-20 is issued or when the new I-20 is registered?" SEVP answered, "OPT ends when the new I-20 is registered." In that call, SEVP clarified the difference between when OPT ends for transfers (when released) versus for changing education levels (when registered). The difference lies in the fact that the reporting requirement ends for the school when the student is released to the transfer-in school, while the reporting requirement does not end when a student does a Change Education Level.