I'm not sure I understand the question. By passive tactile sensibility are you describing an awareness of the implants, A sense of tension or tightness between the two implants?
Maybe this patient has mild allergy to these implants, maybe self-physique, aging of the implant surface (surface degradation or tear off), or the residual particle of surface treatment on implants..., all of the situation would let cells excluded it as foreign body, so induced chronic inflammation then passive tactile sensibility would be arisen.
Many thanks for your intersting question, to the best of my knowledge the paasive tactile sensation in the dental implant is not fully understood yet, especially with those factors that you had mentioned them.
I may advise you to go through the paper in the link below, please
http://sbdmj.lsmuni.lt/103/103-03.pdf
I will be happy for any further elucidation and even collaboration in this topic.
I hope that my understanding to your question was correct.