C++ concurrency::concurrent_vector - c++

Question

I am having issues with the following piece of code while using threads.
I read on the Microsoft site that appending to the concurrent_vector does not mess with iterators, so I did not provide and mutex for the duration of the find_if operation.
So the error I am receiving is an "Access violation"
I have 6 threads running concurrently. Should I wrap this in a mutex? Does it need one. I'm fairly new to C++.
std::stringstream key;
key << "SearchString " << ID << ", " << "Options" << ", " << Date;
auto &it = std::find_if(
m_spList.begin(), m_spList.end(),
[&key] (std::unique_ptr<IBaseObject>const &bo){
return bo->ID() == key.str();
}
);
if (it != m_spList.end()) {
while (it != m_spList.end()) {
ReplacePartResult* rpr = dynamic_cast<ReplacePartResult*>(it->get());
if (rpr) {
if (rpr->ReplaceItem) {
replaceBOMID = rpr->BOMID > 0 ? rpr->BOMID : 0;
if (_parentPart) {
_parentPart->TemplateBomID = rpr->BOMID;
_parentPart->Name = rpr->Name;
_parentPart->Description = rpr->Description;
}
}
}
it = std::find_if(
++it, m_spList.end(),
[&key](std::unique_ptr<IBaseObject>const &bo){
return bo->ID() == key.str();
}
);
}
}

Answer 1

Not 100% why, but i re-factored the find_if into a new function and explicitly defined my iterator type and it seems to be behaving. Maybe sening the stringstream into the lambda was the issue?
concurrency::concurrent_vector<std::unique_ptr<IBaseObject>>::iterator IBaseObject_FindKey(concurrency::concurrent_vector<std::unique_ptr<IBaseObject>>& mv, std::string const& _key)
{
return std::find_if(std::begin(mv), std::end(mv), [&_key](std::unique_ptr<IBaseObject>const &bo){return bo->ID() == _key; });
}