Error: Attempt to assign property "預算金額" on null

• /srv/code/openfun.app/budgetdata/views/budget_proposal/unit_project.php:18
• /srv/code/openfun.app/budgetdata/mini-engine.php:427
• /srv/code/openfun.app/budgetdata/views/budget_proposal/unit.php:13
• /srv/code/openfun.app/budgetdata/mini-engine.php:427
• /srv/code/openfun.app/budgetdata/mini-engine.php:458
• /srv/code/openfun.app/budgetdata/mini-engine.php:292
• /srv/code/openfun.app/budgetdata/mini-engine.php:254
• /srv/code/openfun.app/budgetdata/index.php:4