I've validated that upstream 1.5.32-rc1 fixes this. Thanks to наб for kindly building the packages :)
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_key>... Yannick Le Pennec
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_ke... Yannick Le Pennec
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_ke... наб
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_ke... Yannick Le Pennec
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_ke... Emmanuel Fleury
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_ke... Emmanuel Fleury
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_ke... Raphaël Halimi
- Bug#1098736: ibus 1.5.32~beta2-2 breaks <dead_ke... Yannick Le Pennec

