Unexpected Container.on_animation_end call inside the BottomSheet when it is opened

[lastdayafter]

Duplicate Check

• I have searched the opened issues and there are no duplicates

Describe the bug

If the Container inside the BottomSheet is assigned the animate and bgcolor attributes, along with the on_animation_end handler, the handler will be called when the BottomSheet is opened.

The behavior changes if the bgcolor attribute is None.

Code sample

Code

import flet as ft


class TestItem(ft.Container):
    def __init__(self, *args, **kwargs):
        
        super().__init__(*args, **kwargs)
        # issue with animate and bgcolor
        self.bgcolor = ft.Colors.PRIMARY_CONTAINER
        self.animate = ft.Animation(300, ft.AnimationCurve.EASE)
        self.on_animation_end = self.test_issue
        self.content = ft.Text('Test')

    def test_issue(self, _):
        print('if bgcolor is defined, then on_animation_end will be called')


sheet = ft.BottomSheet(
    content=ft.Column(
        controls=[TestItem() for _ in range(10)],
        scroll=ft.ScrollMode.AUTO, width=400
    )
)


def main(page: ft.Page):
    page.floating_action_button = ft.FloatingActionButton(
        icon=ft.Icons.ADD, on_click=lambda e: e.page.open(sheet)
    )
    page.update()


ft.app(main)

To reproduce

1. Run the code
2. Click the floating button
3. See the print output in the terminal

Expected behavior

No response

Screenshots / Videos

Operating System

macOS

Operating system details

Sequoia 15.2

Flet version

0.26.0

Regression

Yes, it worked as expected in 0.25.2

Suggestions

No response

Logs

Additional details

No response