Upgraded Doulos SIL to 5.000

I just upgraded Doulos SIL from 4.112 to 5.000. Now my plain text files don’t look right anymore.

For example, if I put U+0251 U+0303 into a utf8 text file and look at it with a text editor such as UltraEdit 17.0, I see as expected one unicode character, a back-a with a tilde over it, in almost any font I use. This is what I saw too with Doulos 4.112, but with 5.000 I see something different which, when sufficiently enlarged, turns out to be a back-a with a breve over it and a tilde over that. If I type a space after it, instead of seeing a space, a thing like a small c appears to the right, level with the breve.

There must be some logic to this — can anyone explain it, or tell me how to see in Doulos SIL 5.000 what other fonts including 4.112 show me. Does it mean that 5.000 is too smart for my text editor?

Thanks for your help.

Problem has disappeared as mysteriously as it appeared. There must have been something unfinished about the installation of 5.000, which has since finished.