The problems you've described are both solved by adding a small circle base plate to the center hole of each Barrier. Full details of this modification can be found in the list of permitted Field modifications at the end of Appendix A of the Spin Up Game Manual.
This modification is recommended for all Spin Up Fields. Barriers that shift as described in your question are expected on unmodified Fields, and do not warrant replays. The Head Referee should verbally caution Teams whose actions seem likely to damage Field Elements on an unmodified Spin Up Field to help prevent <S1> Violations.
As described in Appendix A, if you do not have leftover circle base plates from a previous VRC season, you can contact VEX Support for assistance.