Can someone have quiet BPD, but it doesnt show up until a traumatic event?

[LostPossum]

It seemed like my ex was seemingly normal at the time, but after 5 years together a traumatic event happened and she began to show many of the signs of quiet BPD.

Before the traumatic event on occasion she would show some of them, but nothing like compared to that after the traumatic event.

I heard somewhere that trauma and traumatic events can be the catalysts or trigger for quiet BPD individuals to show their true sides or the parts of them they tend to internalize since they are quiet BPD individuals.

Is this true?

Can trauma trigger quiet BPD individuals to finally show signs?

TLDR: small signs of quiet bpd I never really noticed due to rose tinted glasses, trauma occurred, then major signs happening.

[GettingOOTF]

We all have PD traits on occasion. Part of the criteria for being diagnosed with a PD is consistently exhibiting these behaviors over time.

No one here can say whether your ex has Quiet BPD. It's quite possible that the behaviors she exhibited after the trauma were a result of the trauma rather than an underlying PD. Trauma does all kinds of things to the brain and any kind of trauma can result in PTSD, which can easily be confused with a PD. 

I know it was very important for me to get a diagnosis for my ex, for there to be some kind of explanation for how he behaved and how he treated me. I also know that some of the behaviors I didn't like were a result of things I did and the stress of the relationship vs purely his PD. People  are very complex. PDs add another layer to that complexity and PTSD even more so.

Anything is possible but it's impossible for any outsider to diagnose someone.