Is the 4th letter a valid russian character?
When I copy the above word it is automatically converted to "сведения".
The character "д" is the lowercase italic version of "Д", which both derive from the greek letter Delta (compare with "Δ", "δ"). In most fonts the straight lowercase letter is written as "д", while "д" is used in italic type. In some fonts (typically monospace console fonts or fonts designed for headings: Tahoma, Lucida Console, Franklin, Arial Bold, Century, Courier New) "д" is used in both straight and italic types. Capital letters are always written as "Д", even in italic type: "Д".
To make things even more confusing, there is Russian cursive, or handwriting, which has different glyphs. In cursive, "д" will become similar to the Latin letter "g". In the picture below, it's the first letter on the last line:
It is a valid letter "д", the fifth letter of the alphabet. The glyph in the example is produced with a cursive/italic font. The other one is a glyph from a regular straight font.
Every language has its quirkiness. With Russian,this is evident when one starts typing texts on a PC - and then formatting parts of it. Hence, the сведения seems to differ from "сведения". But, this is solely due the use of italics.
This can be easily verified by copying "сведения" twice without a particular format, then mark one of these Russian words; changing its format to italics results in the text as you previously presented this word.
In my experience, attempting to find a font that shows no visible change when italicised is simply too time-consuming. Once one is aware of these Russian text quirks, one can concentrate on Russian cases and declensions!