Upvote:2
The phenomena you mention is so common it has a name. BuJu or JuBu. In fact, there's even a Wikipedia Page on it. Furthermore, the contribution to (Western) Buddhism by Jews is very impressive!
Whether this is frowned upon depends on how your Jewish faith and Buddhist practice relate. Whether they contradict, co-exist or complement depends in turn on how you regard each.
Since Buddhism can be treated as a secular philosophy (which is how I treat it), I see no inherent conflict. This means typical problem points like Buddhism's "atheism", Karma and Rebirth are non-issues.
Even Buddhism's Emptiness (especially our lack of a "self") is not an issue (IMO) if we treat this as a statement about our experience or an injunction against clinging to these beliefs (as opposed to asserting one or the other).