The Abstract Multiplicative Cyclic Groups subsection of the Sage examples in chapter four states that comparison of subgroups is not implemented. The file src/cyclic.xml line 2265 shows the expected output as False. The version of sage included in the online version returns True as shown in the following screenshot.
I could not find anything in the Sage patch notes about a change to the comparison operator for subgroups, but the behavior appears to have changed.
Thank you so much for releasing this book. Working through it has been rewarding.