So by modifying the reqs. for Fusion Explosives by removing the extra req. added by the Fix pack, it now works.
From this:
<Row ss:AutoFitHeight="0" ss:Height="63.75">
<Cell><Data ss:Type="String">Researches.FusionExplosives</Data></Cell>
<Cell ss:StyleID="s72"><Data ss:Type="Number">240</Data></Cell>
<Cell ss:StyleID="s73"><Data ss:Type="String">Weaponary</Data></Cell>
<Cell><Data ss:Type="String">Researches.AlienFusionReactor(AND)Researches.PlasmaExplosives</Data></Cell>
<Cell ss:StyleID="s74"/>
<Cell ss:StyleID="s74"><Data ss:Type="String">UnlockKnowledge( "Researches.FusionExplosives" ); UnlockKnowledge( "Researches.FusionWarheads" ); UnlockKnowledge( "AV.XFPHYPERMISSILE" ); UnlockKnowledge( "AV.XFPFUSIONTORP" ); ReplaceItem("AV.PLASMAMISSILE","AV.HYPERMISSILE"); ReplaceItem("AV.PLASMATORP","AV.FUSIONTORP"); ReplaceItem("weapon.grenade.plasma","weapon.grenade.fusion"); ReplaceItem("weapon.rocket.plasma","weapon.rocket.fusion");</Data></Cell>
<Cell ss:StyleID="s65"><Data ss:Type="String">Researches.FusionExplosives;Researches.FusionWarheads;AV.XFPHYPERMISSILE;AV.XFPFUSIONTORP</Data></Cell>
</Row>
To this:
<Row ss:AutoFitHeight="0" ss:Height="63.75">
<Cell><Data ss:Type="String">Researches.FusionExplosives</Data></Cell>
<Cell ss:StyleID="s72"><Data ss:Type="Number">240</Data></Cell>
<Cell ss:StyleID="s73"><Data ss:Type="String">Weaponary</Data></Cell>
<Cell><Data ss:Type="String">Researches.AlienFusionReactor</Data></Cell>
<Cell ss:StyleID="s74"/>
<Cell ss:StyleID="s74"><Data ss:Type="String">UnlockKnowledge( "Researches.FusionExplosives" ); UnlockKnowledge( "Researches.FusionWarheads" ); UnlockKnowledge( "AV.XFPHYPERMISSILE" ); UnlockKnowledge( "AV.XFPFUSIONTORP" ); ReplaceItem("AV.PLASMAMISSILE","AV.HYPERMISSILE"); ReplaceItem("AV.PLASMATORP","AV.FUSIONTORP"); ReplaceItem("weapon.grenade.plasma","weapon.grenade.fusion"); ReplaceItem("weapon.rocket.plasma","weapon.rocket.fusion");</Data></Cell>
<Cell ss:StyleID="s65"><Data ss:Type="String">Researches.FusionExplosives;Researches.FusionWarheads;AV.XFPHYPERMISSILE;AV.XFPFUSIONTORP</Data></Cell>
</Row>
I think these extra req. flags (such as Researches.PlasmaExplosives) got messed up in the new version, since they are there for, lets say Plasma Explosives themselves, but I didn't encounter this issue back then when researching Plasma stuff (a week ago, running 0.34.2HF), and I have added no relevant mods since then.