Another very serious bug in Maple.

I have code that simplifies intitial conditions passed.

I found that simplify((D@@2)(y)(Pi) = 0) gives error 

Error, (in unknown) invalid input: diff received Pi, which is not valid for its 2nd argument

but Pi is constant. It works for any other values other than Pi.

This only happens when adding Physics:-Setup(assumingusesAssume = true):

Any idea why this happens?

Download simplify_fail_when_adding_physics_sept_27_2025.mw

any idea what match fail on this example? is somethinbg wrong I am doing?

Download why_match_fail_sept_21_2025.mw

Update:
I think match can only do it if the main "variable"   is a variable and not a "function". In this example y(.) is function, so that is why it failed to match. For example this works:

A:=2*y^3+4;
match(A=k1*y^k2+k3,y,'la')

And gives true, since "y" here is not a "function".

But this makes match not very useful to use for parsing. patmatch seems a little more practical to use.

I wanted to check that the input  has the pattern   symbol(symbol), which will match any of   y(x), or f(x) or A(B) and so on.

But using patmatch does not work. Using patmatch(h(z),y::symbol(x::symbol),'la');  or even patmatch(h(z),'y'::anything('x'::anything),'la'); all return false. I know I can do patmatch(h(z),func::function(name),'la'); and this returns true, but this matches h(z,r) and matches h(z,r,t) and matches h(z,r,t,u) and so on. 

I wanted to match only   SYMBOL(SYMBOL), i..e. one symbol followed by "(" followed by one symbol followed by closing ")"

For reference, this is what I am looking for 

I know I can use other ways in Maple to do this (may be typematch and and others). But wanted to see if patmatch works on this and why it is failing.

Can this be done using patmatch?

Maple 2025.1 unable to solve this ode. Sympy gives the following two solutions which Maples verifies are correct.

Any trick or option that can help dsolve find these solutions?
 

Download How_to_find_solution_sept_20_2025.mw

update:

OK, found out how. Needed transformation u(x)=sin(y(x)). Maple probably did not have this in one of the things to try.

Download How_to_find_solution_sept_20_2025_V2.mw

Any idea why Maple dsolve can't find solution to this ode? From textbook

The strange thing, it solves if it asked for implicit solution. But the default, will give no solution.

Is this a defect? Should it not have returned the book solution automatically?   How is a user supposed to know the ode has a solution or not, if default call returns no solution?

Download dsolve_gives_no_solution_sept_2_2025.mw