Should I avoid investing in project that used bridge financing?

Bridge financing should be contemplated and clearly disclosed/documented in the project documentation. It is facts and circumstances and you should consult an experienced EB-5 immigration attorney to review the offering documents for you to answer your questions.

I would inquire as to why the previous investors backed out. I would proceed carefully and engage the services of a qualified EB-5 attorney.

No; the proper use of "bridge financing" need not be avoided. The USCIS Policy Memo of May 30, 2013 provides a clear explanation and confirmation that bridge financing is permissible. Therefore, its existence in any EB-5 project is not reason, in and of itself, to avoid the project. You should consult with an experienced EB-5 immigration attorney for the immigration and legal issues, and you should consult a financial adviser, who can advise you on the due diligence matters.

Many EB-5 projects use bridge financing, which is acceptable from an immigration law perspective. You should review business plans and all offering documentation with an immigration attorney (for immigration law matters) who can also coordinate a team of professionals who can review for non-immigration law matters.

Bridge financing by itself is not a problem as that means the bank or whomever is providing the financing is convinced the project is good. I would be more concerned about why the investors backed out and the solidity of the project itself, their immigration track record, etc.

You need to go with a regional center that is established and has the expertise regardless of whether they use bridge financing. With delays in approval becoming longer, more and more regional centers rely on bridge financing. The USCIS in its 2013 memo specifically approved the use of bridge financing which is replaced with EB-5 capital.