>The sequence uj "new" exists in Hungarian and seems stable.
This is irrelevant here. /ui/ is meant in the Romanian word uiagä only.
BUT: the pronunciation of it is by no means */ui-a-g&/, but
/u-'ya-g&/. And the variant of it, without /u/ (which belongs to my
own subdialect) sounds like this: /'ya-g&/. With the definite article
it's pronounced as... "Baba Yaga" in the Russian tales. :-)
So, the /u-'ya-/ and /'ya-/ are mere awkward attempts to render a rest
of Hungarian üv-. (Romanian doesn't have /ö/ and /ü/.)
Also note the bi-syllable occurrence in both Hung. and Rum. words:
üveg /ü-vaeg/ - uiagä /u-ia-/. I.e., no */üv-eg/, no */ui-a-/.
George