Perhaps we're talking about different things.

Meaning

Perhaps we have different subjects in mind.

Examples

• John: '<b>Perhaps we're talking about different things</b>. Are you referring to Project A or Project B?'
• Alice: 'Project B.'
• John: 'You're right.'
• Alice: '<b>Perhaps we're talking about different things</b>. I thought we were discussing the budget, not the timeline.'