I believe the wording in one of the scenarios of my user test might be mis-leading the participant to click somewhere else on my prototype. I have already tested two participants and this is what raised my concern but I have six more participants to test. Before I continue testing, is it ok to change the wording in the scenario for the remaining six participants? Does changing the scenario effect the validity of the results?
A good rule of thumb when creating scripts for user testing for your scenarios is to build in a little bit of flexibility for situations like this. But as the comments suggest it really depends on that particular question as well as the rest of the tasks in your user test.
Generally I try to focus on the information that I need to obtain from the users rather than following a strict script and just see what information they will offer. The reason for this is that unless you are doing a very large study with a very high number of participants, it is difficult to rule out any particular effects that might be affecting the user response and make adjustments in your analysis. For smaller number of participants like an interview, it is hard to tell whether it is just something that a particular participant that is causing the difference in what you are observing.
A really good way to try and rule this out is to just do a dry run of the user test with internal team members don't have any prior knowledge of what you are testing, and that way you might get some idea whether the wording is causing general interpretation issues for specific users or not.