string() with weval-ed WExpr escape (\) some characters on arbitrary precision floating numbers with back quote

Here is an example session:

julia> set_GreedyEval(false)
false

julia> a=W`17.00000000000000000000000000000`
17.`30.230448921378276

julia> string(a)
"17.`30.230448921378276"

julia> W"Sin"(W"Sqrt"(a))
W`Sin[Sqrt[17.`30.230448921378276]]`

julia> string(W"Sin"(W"Sqrt"(a)))
"W`Sin[Sqrt[17.`30.230448921378276]]`"

julia> weval(W"Sin"(W"Sqrt"(a)))
-0.8313391791635062080451600446002018832298332563980832506813`30.091141206520284

julia> string(W"Sin"(W"Sqrt"(a)))
"W`Sin[Sqrt[17.\0`30.23044892137827]]`"

In the output of the last command, the 0 after the dot is escaped. In fact I have encountered this issue several times with back quote in "Real" numbers. Note that apparently this only happens if 'weval' was used on the WExpr. After, it seems no longer possible to restore the previous behaviour:

julia> string(W"Sin"(W"Sqrt"(a)))
"W`Sin[Sqrt[17.`30.230448921378276]]`"

Reproduce the session using set_GreedyEval(false), WExpr construction, weval, and string(). Start by tracing how string() serializes arbitrary-precision real values after weval. Done means back quotes and decimal characters are emitted without spurious escaping, while the reproduced WExpr output remains valid.