When on the mod/lesson/continue.php page, any attempt to change the position of a block through the block configuration page using the Region setting will fail.

This is because the database record in mdl_block_positions is set to a page type of "mod-lesson-view", when the page context when visiting the page is "mod-lesson-continue"

This error is caused by line 172 of mod/lesson/continue.php

$PAGE->set_url('/mod/lesson/view.php', array('id' => $cm->id, 'pageid' => $page->id));

I'm guessing that the reason for this line is to prevent a user being redirected back to this page after login.

In order to have a page context that is the same as this URL setting, I propose changing the page context on continue.php to "mod-lesson-view". This fixes the above problem.