The answer to that question depends on the other church. If you're away from the area and are unable to commune here at Mt. Zion, you should seek out a church which believes and teaches and practices what we do. The only churches in this country which have committed themselves to doing so are the congregations of the Lutheran Church–Missouri Synod. We are not in fellowship with other Christian and Lutheran church bodies because of important differences in what we believe and teach.
You should only commune at a church that has the same teachings and beliefs as Mt. Zion does. To commune at a particular church means that you agree with what that church stands for, its doctrine. A Christian cannot commune at two different churches which do not agree in doctrine. You cannot be in fellowship both with falsehood and with the truth.
Therefore, you should not commune at a non-Missouri Synod Lutheran church or any church (even an LCMS one) which engages in or allows the existence of false teaching or practice in its midst, even if you think that false teaching is only a small matter. The fact is that no false teaching is a small matter, because it threatens the truth of the Gospel of Christ; just as you would regard even a little poison in your food to be a very dangerous thing.
This is not only a private matter between you and the Lord. By communing you are also uniting yourself with the others who commune with you and with the teaching that is proclaimed in that place. Receiving communion is a public act by which we proclaim the Lord's death until He comes (I Corinthians 11:26). May God grant all His churches to make this Gospel proclamation clearly and purely to His glory and the salvation of many!