Community property does not lose its character by virtue of a move to a non-community property state.  When spouses are domiciled in different states, a court will determine the character of the property by the law of the state in which the spouse who acquired the property was domiciled at the time of its acquisition.

Property acquired by either spouse in a non-community property state is not converted into community property by the mere act of taking it into a community property state and establishing a domicile there.  For instance, in Washington, personal property acquired by either husband or wife in a foreign jurisdiction, which is by law of the place where acquired the separate property of one or the other of the spouses, continues to be the separate property of that spouse when brought within Washington State.  It being the separate property of that spouse owning and bringing it into Washington State, property in the state, whether real or personal, received in exchange for it, or purchased by it if it be money, is also the separate property of such spouse[i].

Therefore, personal property acquired while the spouses are domiciled in a state whose laws make it the property of the acquiring spouse does not lose its character as a result of a subsequent removal of the domicile, with or without the property, into a state where the community property law prevails.  The property acquired in the original domicile retains its original form after being brought into the new domicile, or is traceable to other property acquired in the new domicile.  The change of domicile has no effect on the status, as separate or community, enjoyed by the property when acquired in the original domicile[ii].

The most common issue governed by a determination of the character of property brought from a non-community state where it was the separate property of one spouse into a state where, if it had been acquired there, it would have been community property, is the succession to such property, or other property into which it is traceable, on the death of one of the spouses.  Frequently the succession to property of a deceased spouse in states following the community property system is different according to whether particular property is community property or the separate property of one of the spouses.
 

[i] Meyers v. Albert, 76 Wash. 218 (Wash. 1913) 

[ii] 14 A.L.R.3d 404, 2b