Hi CodeCat! *blējanan ("to bleat, howl"; > OHG blāen (weak verb), MLG bleken, German blöken, and perhaps Scots blea, all meaning "bleat") is a separate verb from *blēanan ("to blow"). Koebler has it with intermediary -j-. I left it there because I was not sure if this is due to suffixation (maybe it should be *blēijanan?), or whether to remove if -j- always disappears in PGmc. Can you please confirm? If the two verbs do share the same form, I will need to break out a separate etymology.
Ringe says that loss of -j- occurred everywhere except after -i-, so going by what he said, this must be something else. It is a good question though. By the natural operation of sound changes, some class 1 weak verbs would have lost their -j-, if they had stems ending in vowels. I wonder what happened to them, and whether this is an example.