Has anyone ever heard of probiotics triggering neurological symptoms/problems?

Perhaps. Depends what you mean by symptoms. There have been studies suggesting that gut microbes interact with the CNS "not only with the enteric nervous system but also with the central nervous system via neural, neuroendocrine, neuroimmune and humoral links." Since probiotics may alter gut flora. It is plausible. More here http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3555881/pdf/gmic-4-17.pdf.