difference in lmer results with REML = FALSE and refitML

I've logged this at https://github.com/lme4/lme4/issues/202 .

Henrik Singmann <henrik.singmann at ...> writes:

Dear list,

based on a question on the sister list for linguistics
(http://thread.gmane.org/gmane.comp.lang.r.linguistics/844/focus=846) 
I came across some weird
inconsistencies when comparing a lmer fit with REML = FALSE 
and the same model first fitted with REML and
then refitted with ML. The strange behavior is that both ML
 fits do not agree. This seems to be somewhat unexpected.

See case below.

Cheers,
Henrik

I do at least get convergence warnings (with my current
development version of lme4) for the second, suboptimal fit.
I should look at slices to see what the surface looks like
(i.e. where the suboptimal stopping point is), and how this
behaves with other optimizers.

  thanks
    Ben Bolker