From the Site Home, entering any string containing an & (ampersand) character causes the string & to be displayed in the Module search results returned e.g. searching for "10 & 20" or just "&" will produce this outcome.
This appears to be a display issue only in the search results. If you click on the module listed with & in the title it takes you to the correct module and the module is displayed normally.
Similar issues have been reported for Moodle and there are suggestions that this was associated with the Boost Theme. See https://moodle.org/mod/forum/discuss.php?d=359832 which we are using.
However I have tested this on a Moodle 3.2 system with the standard out-of the-box theme and this still occurs, so this appears to be an issue with Moodle Core Code.