When launching the app on iPhone with the UI refresh flag enabled, some constraints are breaking:

(
    "<NSLayoutConstraint:0x608000290590 UIImageView:0x7fcf08521de0.height == 28   (active)>",
    "<NSLayoutConstraint:0x6080002906d0 V:|-(8)-[UIStackView:0x7fcf08522a90]   (active, names: '|':UITableViewCellContentView:0x7fcf08521a70 )>",
    "<NSLayoutConstraint:0x608000290720 UIStackView:0x7fcf08522a90.bottom == UITableViewCellContentView:0x7fcf08521a70.bottom - 8   (active)>",
    "<NSLayoutConstraint:0x6080002911c0 'UISV-canvas-connection' UIStackView:0x7fcf08522a90.top == _UILayoutSpacer:0x6080001d4cd0'UISV-alignment-spanner'.top   (active)>",
    "<NSLayoutConstraint:0x608000291260 'UISV-canvas-connection' UIStackView:0x7fcf08522a90.centerY == UIImageView:0x7fcf08521de0.centerY   (active)>",
    "<NSLayoutConstraint:0x608000290f40 'UISV-spanning-boundary' _UILayoutSpacer:0x6080001d4cd0'UISV-alignment-spanner'.top <= UIImageView:0x7fcf08521de0.top   (active)>",
    "<NSLayoutConstraint:0x6080002918f0 'UIView-Encapsulated-Layout-Height' UITableViewCellContentView:0x7fcf08521a70.height == 44   (active)>"
)

Checking the super-super-superview of the stack view, it seems that it is the table view displaying the recent tabs in the TabGrid.