I've encountered a bug in the lesson module that may be related to this issue in at least two builds of 1.9.4+. I'm currently running 1.9.4+ (Build: 20090218).
Environment: php 5.2.8, V1.9.4+ (Build: 20090218), MySQL 5.0.67-community, Apache 2.2.11 (Unix), Perl 5.8.8, Operating system Linux Kernel 2.6.28
Any time a question includes a short answer, the question attempt is recorded. However, the response is not recorded as correct even if it was correct. This causes the student score to be incorrect. The lesson pages process correctly. The correct feed back is displayed. Everything appears to work perfectly, except that he total score for the lesson is not incremented properly.
Between my hosting company and myself, we have done some fairly extensive trouble shooting, and it looks like it is a bug.
This is really becoming a problem on our site!